Browse All 300+ Free Calculators

Basic Calculator

Free online calculator with memory functions, keyboard support, calculation history, and floating-point correction. Add, subtract, multiply, and divide instantly.

Exponent Calculator | bⁿ, Roots & Logarithms

Calculate any base raised to any power (bⁿ), find the base given a result and exponent, or solve for the exponent using logarithms. Handles negative, fractional, and zero exponents with step-by-step working.

Scientific Notation Calculator

Convert numbers to and from scientific notation and perform arithmetic in scientific notation.

Modulo Calculator | Remainder Division

Calculate the remainder of a division (modulo operation) for any two numbers.

Nth Root Calculator | Square & Cube

Calculate any nth root of a number including square root, cube root, and custom roots.

Number Sorter | Sort & Statistics

Sort a list of numbers in ascending or descending order. Find min, max, sum, and average.

Remainder Calculator | Long Division with Steps

Calculate the quotient and remainder of any division with full long division working shown step by step. Also computes the modulo and checks divisibility for multiple divisors at once.

Recipe Scaling Calculator | Multiply or Divide Servings

Scale any recipe up or down by servings or a custom multiplier. Convert between cups, tablespoons, teaspoons, and grams. Handles fractions, adjusts pan sizes, and notes ingredients that do not scale linearly.

Advanced Scientific Calculator

A CAS-level scientific calculator with graphing, matrices, complex numbers, derivatives, integrals, statistics, and equation solving, all in one.

GPA Calculator | Weighted & Cumulative GPA with What-If

Calculate weighted GPA for a semester or cumulatively across all years. Supports letter grades with +/− and custom grading scales. Built-in what-if analyzer shows the exact grades needed to reach your GPA target.

Percentage Calculator

Calculate percentages easily. Find what percent one number is of another, increase or decrease by a percentage, and more.

Percentage Change Calculator

Calculate the percentage increase or decrease between two values quickly and accurately.

Markup Calculator | Profit & Selling Price

Calculate markup percentage, selling price, and profit margin from cost and revenue.

Percentage Discount Calculator

Calculate sale price, discount amount, and savings percentage for any original price.

Percentage Error Calculator

Calculate the percentage error and absolute error between a measured and true value.

Average Calculator | Mean, Median & Mode

Calculate the mean, median, mode, standard deviation, IQR, box plot, and more for any dataset.

Weighted Average Calculator

Calculate the weighted average of values with different weights.

Ratio Calculator | Simplify & Solve

Simplify ratios, find equivalent ratios, and solve ratio problems.

Proportion Solver | Cross Multiply

Solve proportions by finding the unknown value in a/b = c/d equations.

Grade Calculator | Weighted GPA & Final Grade

Calculate weighted final grades, simple averages, and GPA from up to 12 assignments. Find what score you need on remaining work to hit your target grade.

Harmonic Mean Calculator | Rates, Speeds & P/E Ratios

Calculate the harmonic mean of any dataset. Compare H, G, A means, verify AM-GM-HM inequality, see reciprocal table. Weighted harmonic mean mode included.

Fraction Calculator | Add, Subtract & More

Add, subtract, multiply, and divide fractions and mixed numbers with LCM common denominators, cross-simplification, and full step-by-step working.

Fraction to Decimal Converter | Repeating & Terminating

Convert fractions to decimals with repeating-block detection, or convert terminating decimals back to simplified fractions. Supports mixed numbers and shows full step-by-step long division working.

Mixed Number Calculator | Add & Divide

Add, subtract, multiply, and divide mixed numbers. Converts between mixed numbers, improper fractions, and decimals with step-by-step working.

Unit Converter | Length, Weight & More

Convert between units of length, weight, temperature, volume, and more.

Number Base Converter | Binary, Hex

Convert numbers between binary, octal, decimal, and hexadecimal bases.

Speed Converter | mph, km/h, m/s

Convert between mph, km/h, m/s, knots, and feet per second.

Temperature Converter | °C, °F, K

Convert between Celsius, Fahrenheit, Kelvin, and Rankine temperature scales.

Energy Converter | Joules, kWh, BTU & Calories

Convert between 15 energy units: joules, kJ, MJ, GJ, Wh, kWh, MWh, cal, kcal, BTU, therm, ft·lb, eV, keV, MeV. Live results organized by category with smart formatting and NIST-sourced conversion factors.

Pressure Unit Converter

Convert between Pascal, psi, atm, bar, mmHg, and torr pressure units.

Data Storage Converter | Bytes, KB, MB, GB & TB

Convert between bits, bytes, KB, MB, GB, TB, PB and binary KiB, MiB, GiB, TiB units. Explains the 1 TB = 931 GB discrepancy between SI and IEC standards.

Fuel Efficiency Converter | All Units

Convert fuel efficiency between L/100km, MPG US, MPG UK, km/L, gal/100mi, and mi/L simultaneously. Includes efficiency rating and vehicle class comparison.

Angle Converter | Degrees, Radians, Gradians & More

Convert angles between degrees, radians, gradians, turns, arcminutes, arcseconds, and milliradians. Includes DMS mode and a visual angle display.

Power Unit Converter | Watts & HP

Convert between watts, kilowatts, horsepower, BTU/h, and other power units.

Shoe Size Calculator | US, UK, EU & International Size Conversion

Convert shoe sizes between US, UK, EU, Japanese, Mexican, and Brazilian sizing systems for men, women, and kids. Enter foot length in inches or centimeters for a precise size recommendation, or convert from any known size system to all others including width guidance.

Ring Size Calculator | Find Your Ring Size from Finger Measurements

Find your exact ring size from finger circumference or diameter in millimeters or inches. Converts between US/Canada, UK/Australia/South Africa, EU/ISO, and Asian sizing systems. Includes a printable paper ring sizer template and resizing guidance by metal type.

Quadratic Equation Solver

Solve quadratic equations (ax² + bx + c = 0) and find both real and complex roots.

Cubic Equation Solver | ax³+bx²+cx+d=0

Solve cubic equations (ax³ + bx² + cx + d = 0) and find all three roots with step-by-step working, graph, and factored form.

Polynomial Evaluator | Compute f(x)

Evaluate any polynomial at a given value of x using Horner method.

Logarithm Calculator | Log & Ln

Calculate logarithms with any base. Supports natural log (ln), log base 10, and custom bases.

Absolute Value Equation Solver

Solve |ax + b| = c and |ax + b| = |cx + d| with step-by-step case analysis, verification, and formatted solutions.

Linear Equation Solver | Solve ax+b=c

Solve linear equations in one variable (ax + b = c) with step-by-step solutions.

Systems of Equations Solver 2×2

Solve systems of two linear equations with two unknowns using Cramer's rule.

Inequality Solver | Linear & Quadratic

Solve linear and quadratic inequalities with step-by-step solutions.

Summation Calculator | Sigma Notation

Evaluate summation expressions with custom formulas, bounds, and step values.

Complex Number Calculator | a+bi

Add, subtract, multiply, divide, and apply powers and logs to complex numbers. Shows Argand diagram, polar form, modulus, and step-by-step working.

Completing the Square Calculator

Convert ax² + bx + c to vertex form a(x−h)² + k step by step. Find the vertex, axis of symmetry, and roots of any quadratic.

Synthetic Division Calculator

Divide polynomials using synthetic division and find quotient and remainder.

Rational Root Theorem Calculator

Find all possible rational roots of a polynomial using the Rational Root Theorem.

Exponent Rules Calculator | All 8 Laws

Apply all 8 laws of exponents, product, quotient, power of a power, zero, negative, fractional, and multiple-base rules, with step-by-step working and numerical verification for any base and exponents.

Logarithm Laws Calculator

Apply logarithm laws: product, quotient, power, change of base, and natural log rules.

Arithmetic Sequence Calculator

Find the nth term, partial sum, and common difference of any arithmetic sequence. Solve for any unknown and generate up to 1,000 terms.

Geometric Sequence Calculator | nth Term & Sum

Find the nth term, partial sum, and infinite sum of any geometric sequence. Solve for the common ratio or number of terms. Determine convergence with first 12 terms shown.

Simplify Radicals Calculator

Simplify radical expressions by extracting perfect square (or nth-power) factors. Converts √72 → 6√2, ∛54 → 3∛2, and handles variables.

Exponential Growth & Decay Calculator | y = aeʳᵗ

Calculate exponential growth or decay using y = ae^(rt). Solve for any unknown: initial value, growth/decay rate, time, or final value. Covers population growth, bacterial cultures, radioactive decay, investment compounding, and any continuous growth model. Doubling and half-life shown automatically.

Polynomial Long Division Calculator | Step-by-Step Quotient & Remainder

Divide any polynomial P(x) by any divisor Q(x) using full long-division notation. Shows every multiply-subtract step exactly as you would write it by hand, outputs the quotient and remainder, reconstructs the original polynomial for verification, and checks if Q(x) is an exact factor.

Area Calculator | 11 Shapes with Formulas & Perimeter

Calculate area and perimeter for 11 shapes: rectangle, square, circle, triangle, right triangle, trapezoid, parallelogram, rhombus, ellipse, hexagon, and sector. Formulas shown with your values substituted in.

Volume Calculator | 3D Shapes

Calculate the volume of cubes, spheres, cylinders, cones, and other 3D shapes.

Perimeter Calculator | 2D Shapes

Calculate the perimeter and circumference of common 2D shapes.

Pythagorean Theorem Calculator

Find the missing side of a right triangle using a² + b² = c².

Distance Calculator | 2D & 3D Points

Find Euclidean, Manhattan, and Chebyshev distance between 2D or 3D points. Includes midpoint, slope, line equation, and SVG visualization.

Midpoint Calculator | Two Points

Find the midpoint between two points in 2D or 3D coordinate space.

Slope Calculator | Gradient & Line

Calculate the slope of a line between two points and find the line equation.

Circle Calculator | Area & Circumference

Calculate radius, diameter, circumference, and area of a circle from any known value. Supports sector angle input for arc length, sector area, chord length, and segment area. Includes 7 unit options, adjustable precision, SVG diagram, and 5 real-world presets.

Surface Area Calculator | Box Surface Area & 3D Shapes

Calculate surface area of cubes, spheres, cylinders, cones, and other 3D shapes.

Triangle Solver | Law of Sines & Cosines

Solve any triangle given SSS, SAS, ASA, or AAS using law of sines and cosines.

Coordinate Geometry Calculator | Distance & Slope

Calculate distance, midpoint, slope, line equation, angle, section point, and triangle area from coordinates. Includes an interactive coordinate plane diagram, triangle analysis (centroid, inradius, circumradius), and step-by-step working.

Ellipse Calculator | Area, Perimeter & Eccentricity

Calculate the area, perimeter (Ramanujan II), eccentricity, focal distance, semi-latus rectum, directrix, flattening, and standard equation of any ellipse from its semi-axes.

Regular Polygon Calculator

Calculate the area, perimeter, interior angles, and diagonal of any regular polygon.

Heron's Formula Calculator, Triangle Area & Angles

Calculate triangle area using Heron's formula (SSS), SAS, or base-height. Shows all angles via law of cosines, altitudes, triangle type, SVG diagram, and step-by-step working.

Circle Sector Calculator | Arc, Area & Chord

Calculate arc length, sector area, chord length, segment area, and perimeter of a circle sector. Supports 4 solve-for modes (r+θ, arc+θ, area+θ, r+arc), degrees or radians, 7 length units, SVG diagram, presets, and step-by-step working.

Torus Calculator | Volume & Surface Area

Calculate the volume, surface area, and other properties of a torus (donut shape).

Golden Ratio Calculator | φ = 1.618033…

Calculate golden ratio dimensions from any measurement. Find A from B, B from A, total length, golden rectangle dimensions. Shows Fibonacci spiral convergence to φ with up to 15 decimal precision.

Frustum Calculator | Volume, Area & Slant Height

Calculate volume, slant height, lateral area, and total surface area of a frustum (truncated cone). Supports 5 units, 6 presets, SVG diagram, and step-by-step working.

Aspect Ratio Calculator | Screen & Image

Calculate aspect ratios, scale dimensions proportionally, and batch-resize images or videos without distortion.

Map Scale Calculator

Convert between map distances and real-world distances using any map scale ratio.

Paint Calculator | Gallons Needed for Walls & Ceilings

Calculate exactly how much paint you need for any room. Enter wall dimensions, doors, windows, and number of coats. Supports walls, ceilings, trims, and exterior surfaces with waste factor.

Flooring Calculator | Square Footage & Materials

Calculate flooring materials for any room shape. Enter dimensions, choose flooring type (hardwood, tile, vinyl, carpet), set waste factor, and get total square footage, boxes needed, and cost estimate.

Conic Section Analyzer | Circle, Ellipse, Parabola & Hyperbola

Analyze any conic section from the general equation Ax²+Bxy+Cy²+Dx+Ey+F=0. Identifies the type, finds center, foci, vertices, asymptotes, and eccentricity, handles rotation when B≠0, and shows full discriminant-based step-by-step classification.

Platonic Solids Calculator | Volume, Surface Area & Radii for All 5 Solids

Compute volume, surface area, inradius (insphere), midradius (midsphere), and circumradius (circumsphere) for all five Platonic solids — tetrahedron, cube, octahedron, dodecahedron, and icosahedron — from a single edge length. Includes face, edge, and vertex counts.

Quadrilateral Area Calculator | Parallelogram, Trapezoid, Rhombus & Kite

Compute the area and perimeter of any quadrilateral: parallelogram, trapezoid, rhombus, kite, rectangle, square, and general quadrilateral by vertex coordinates or side lengths and angles. Includes the Shoelace formula and Brahmagupta's formula for cyclic quadrilaterals.

Trigonometry Calculator | Sin, Cos, Tan

Calculate sine, cosine, tangent, and their inverses for any angle.

Inverse Trig Calculator | Arcsin, Arccos

Calculate arcsin, arccos, arctan and get angles from trig ratios.

Right Triangle Solver | Sides & Angles

Solve any right triangle given two sides or one side and one angle.

Radians to Degrees Converter

Convert angles between radians and degrees instantly.

Unit Circle Calculator | Exact Trig Values

Find exact and decimal values of sin, cos, tan, csc, sec, and cot for any angle on the unit circle. Supports degrees and radians, shows reference angles, quadrant, and coordinates.

Trigonometric Equation Solver | sin, cos & tan Equations

Solve trigonometric equations in the forms a·sin(bx+c)+d=0, a·cos(bx+c)+d=0, a·tan(bx+c)+d=0, and quadratic-in-trig forms like a·sin²x+b·sinx+c=0. Returns exact values at standard angles, the general solution in terms of n, and all solutions in [0, 2π].

Derivative Calculator | Find f′(x) Instantly

Compute 1st through 4th numerical derivatives of any function at any point. Shows tangent line equation, derivative table, and interactive chart.

Second Derivative Calculator

Compute the second derivative and determine concavity at a given point.

Integral Calculator | Numerical

Compute definite integrals numerically using Simpson's rule and the trapezoidal rule.

Limit Calculator | Evaluate Limits

Evaluate limits of functions numerically as x approaches a value from left, right, or both sides.

Riemann Sum Calculator

Approximate definite integrals using left, right, midpoint, and trapezoidal Riemann sums.

Tangent Line Calculator

Find the equation of the tangent line to a function at a given point.

Newton's Method Calculator

Find roots of equations using Newton's iterative method with step-by-step convergence.

Arc Length Calculator | Curves & Circle Arcs

Calculate arc length for any function f(x) over an interval using numerical integration, or compute a circle arc length from radius and angle. Also shows sector area, chord length, and step-by-step working.

Partial Derivative Calculator

Compute partial derivatives of multivariable polynomial functions.

Taylor Series Calculator

Compute Taylor/Maclaurin series expansions for common functions.

Differential Equation Solver | ODE

Solve first-order ODEs numerically using Euler, Heun, and RK4. Compare method accuracy step by step.

Area Between Curves Calculator | Two Functions

Calculate the exact area enclosed between two functions f(x) and g(x) over any interval. Automatically detects intersection points, splits the integral correctly, and shows a sub-region breakdown.

Volume of Revolution Calculator

Calculate volumes of solids of revolution using disc and shell methods.

Laplace Transform Calculator

Find Laplace transforms and inverse transforms for common functions.

Fourier Series Calculator | aₙ, bₙ & Spectrum

Compute Fourier coefficients aₙ and bₙ for any periodic function using 2000-point Simpson's rule. Supports square wave, sawtooth, triangle, rectifiers, and custom expressions. Shows amplitude spectrum, coefficient table, partial sum, and Gibbs phenomenon detection.

Improper Integral Calculator

Evaluate improper integrals with infinite limits or discontinuities.

Series Convergence Calculator

Test if an infinite series converges or diverges using ratio, root, and comparison tests.

Interpolation Calculator | Lagrange, Newton & Divided Differences

Construct an interpolating polynomial through any set of data points using Lagrange interpolation or Newton's divided difference method. Displays the full divided difference table, polynomial in expanded form, and evaluates at any x — with error bound estimation between data points.

ODE Numerical Solver | Euler, Heun & Runge-Kutta RK4

Numerically solve first-order ordinary differential equations y′ = f(x, y) using three methods side-by-side: Euler's method, Heun's method (improved Euler), and the 4th-order Runge-Kutta (RK4). Shows all intermediate k₁–k₄ values for RK4 and a full step-by-step comparison table.

Numerical Differentiation Calculator | Forward, Central & Richardson

Approximate the derivative of any function f(x) at a given point using forward difference, backward difference, central difference (O(h²) accurate), and Richardson extrapolation (O(h⁴) accurate). Also computes the second derivative via the central second-difference formula and shows the truncation error for each method.

Numerical Integration Calculator | Simpson, Gaussian & Trapezoid

Integrate any function f(x) over an interval [a, b] using five methods side-by-side: Trapezoid rule, Simpson's 1/3 rule, Simpson's 3/8 rule, Boole's rule, and 5-point Gaussian quadrature. Compares all results, shows step-by-step working for the selected method, and estimates truncation error.

Wronskian Calculator | Linear Independence & Fundamental Solution Sets

Compute the Wronskian determinant W(f₁, f₂) or W(f₁, f₂, f₃) by evaluating derivatives numerically. Tests linear independence of function sets, identifies fundamental solution sets for linear ODEs, and displays the full derivative matrix evaluated at multiple points.

Standard Deviation Calculator

Calculate standard deviation, variance, and other statistics for a dataset.

Z-Score Calculator | Standard Score & Percentile

Calculate z-score, percentile rank, and p-values from any data point, mean, and standard deviation. Includes reverse calculation and step-by-step solutions.

Probability Calculator | Events

Calculate single event, multiple event, conditional, and complementary probabilities.

Correlation Coefficient Calculator

Calculate Pearson r and Spearman ρ between two datasets with p-value, R², regression line, and scatter plot.

Linear Regression Calculator

Find the best-fit line (y = mx + b) using least squares regression.

Binomial Distribution Calculator

Calculate binomial probability P(X=k), CDF, mean, variance, and distribution statistics for any n and p. Includes bar chart and full probability table.

Poisson Distribution Calculator

Calculate Poisson probabilities for rare event modeling.

Chi-Square Calculator

Perform chi-square goodness-of-fit and independence tests with p-value, critical value, effect size (Cramér's V, Cohen's w), Yates' correction, standardised residuals, and chi-square distribution curve. Supports 2–5×2–5 contingency tables with real-world presets.

Confidence Interval Calculator | Mean & Proportion

Calculate confidence intervals for means (z and t-test) and proportions (Wald and Wilson). Shows margin of error, critical value, SE, step-by-step working, and a visual bell curve diagram.

Sample Size Calculator

Calculate the required sample size for surveys and experiments.

Percentile Calculator | Rank & Value

Find percentile ranks and values from a dataset.

ANOVA Calculator | One-Way with p-value & Effect Size

Perform one-way ANOVA with up to 6 groups. Shows the full ANOVA table, exact p-value, effect size η², group statistics, and a significance verdict, no F-table look-up needed.

Bayes' Theorem Calculator

Calculate posterior probability P(A|B) from prior, sensitivity, and false positive rate. Includes natural frequencies, Bayes factor, and step-by-step derivation.

T-Test Calculator | One-Sample

Perform a one-sample t-test to determine if a sample mean differs significantly from a known value.

Variance Calculator | Population & Sample

Calculate population variance and sample variance from a dataset with step-by-step workings.

Quartile Calculator | Q1, Q2, Q3 & IQR

Calculate Q1, Q2 (median), Q3, interquartile range (IQR), and detect outliers from data.

Frequency Distribution Calculator | Tables & Charts

Build grouped or ungrouped frequency distribution tables from raw data. Shows relative and cumulative frequencies, modal class, estimated mean and standard deviation, and a bar chart.

Geometric Mean Calculator | How to Calculate Geometric Mean

Calculate geometric mean for growth rates, investment CAGR, and multiplicative data. Compare AM, GM, and HM with warnings for zeros and negatives.

Moving Average Calculator | SMA & EMA

Calculate simple moving average (SMA) and exponential moving average (EMA) for time series data.

Effect Size Calculator | Cohen's d, η² & r

Calculate Cohen's d, Hedges' g, Glass's Δ, r, and η² effect sizes from means, t-statistics, F-statistics, or correlation r. Includes 95% CI, power, and required sample size.

P-Value Calculator | Z, T, Chi-Square & F

Calculate the exact p-value from a z-score, t-statistic, chi-square statistic, or F-statistic. Supports one-tailed and two-tailed tests with significance interpretation.

Mean, Median & Mode Calculator

Calculate the mean, median, mode, range, variance, standard deviation, quartiles, and IQR for any dataset. Detects outliers, shows sorted data, and supports both population and sample statistics.

Normal Distribution Calculator | PDF, CDF & Inverse

Compute exact probabilities for any normal distribution: P(X < a), P(X > a), P(a ≤ X ≤ b), inverse CDF (quantile), and PDF at a point. Works with standard normal (μ=0, σ=1) and custom parameters. Bell curve visualization included.

Process Capability Calculator | Cp, Cpk, Ppk & Six Sigma Level

Calculate process capability indices Cp, Cpk, Pp, and Ppk from specification limits and process statistics. Computes the Six Sigma level, DPMO (defects per million opportunities), control chart limits (UCL, LCL), and the probability of a defect. Classifies the process as world-class, capable, marginal, or inadequate.

Box Plot Calculator | Five-Number Summary, IQR & Outlier Detection

Compute the five-number summary (minimum, Q1, median, Q3, maximum) from raw data. Calculates the interquartile range (IQR), inner and outer Tukey fences, and identifies mild and extreme outliers. Shows sorted data, mean, and standard deviation alongside the box plot statistics.

Power Analysis Calculator | Sample Size, Effect Size & Statistical Power

Determine the required sample size for a study given desired statistical power (1 − β), significance level α, and effect size. Supports Cohen's d for t-tests and z-tests, Cohen's h for proportion tests, and Cohen's w for chi-square tests. Also computes achieved power for a given sample size.

Beta Distribution Calculator | PDF, CDF, Mean & Bayesian Inference

Compute the probability density function (PDF), cumulative distribution function (CDF), mean, variance, mode, and skewness of the Beta(α, β) distribution. Evaluates P(X ≤ x) and P(a ≤ X ≤ b) numerically, with applications in Bayesian inference, proportion modeling, and project completion time estimation.

Weibull Distribution Calculator | Reliability, Failure Rate & MTTF

Compute the PDF, CDF, reliability function, failure (hazard) rate, and mean time to failure (MTTF) for the Weibull distribution with shape parameter k and scale parameter λ. Evaluates survival probability at any time t, computes B10 life, and classifies the failure mode: infant mortality, random, or wear-out.

Two-Way ANOVA Calculator | Factorial Design with Interaction Term

Perform a two-way analysis of variance for a factorial design with up to 4 levels per factor. Computes sum of squares, degrees of freedom, mean squares, F-statistics, and p-values for factor A, factor B, their interaction A×B, and error. Reports eta-squared effect sizes and overall model fit.

Multiple Regression Calculator | Coefficients, R², F-Test & Residuals

Fit a multiple linear regression model with 2–5 predictor variables. Computes regression coefficients, standard errors, t-statistics, p-values, R², adjusted R², and F-statistic. Includes variance inflation factor (VIF) to diagnose multicollinearity and residual analysis.

Logistic Regression Calculator | Log-Odds, Odds Ratios & ROC AUC

Fit a binary logistic regression model using iterative gradient descent. Computes log-likelihood, coefficients, standard errors, odds ratios, predicted probabilities, and ROC AUC. Includes confusion matrix with accuracy, precision, recall, and F1 score.

Mann-Whitney U Test Calculator | Non-Parametric Two-Sample Test

Perform the Mann-Whitney U test (Wilcoxon rank-sum test) on two independent samples. Computes U statistic, z-score approximation with continuity correction, exact p-value for small samples, and effect size r = z/√n.

Spearman Rank Correlation Calculator | ρ, t-Statistic & p-Value

Compute the Spearman rank correlation coefficient ρ for two paired data sets with up to 50 observations. Handles tied ranks with the correction factor, computes the t-statistic for significance testing, and produces a confidence interval.

Kruskal-Wallis H Test Calculator | Non-Parametric One-Way ANOVA

Perform the Kruskal-Wallis H test across 2–6 independent groups as a non-parametric alternative to one-way ANOVA. Computes the H statistic, degrees of freedom, chi-square p-value, and pairwise Dunn post-hoc comparisons with Bonferroni correction.

Birthday Problem Calculator | Shared Birthday Probability & Group Size

Compute the probability that at least two people in a group share a birthday using the exact combinatorial formula and Poisson approximation. Find the minimum group size for any target probability, and visualize how probability grows from n = 1 to 100.

Bayes Factor Calculator | BF₁₀, Prior/Posterior Odds & Jeffreys Scale

Compute the Bayes factor BF₁₀ from a likelihood ratio, t-statistic, or chi-square statistic. Updates prior odds to posterior odds, interprets evidence strength on the Jeffreys scale (decisive, strong, moderate, anecdotal), and computes posterior probability of H₁.

Compound Interest Calculator

Calculate compound interest with monthly contributions, solve for principal, rate, or time, and see a year-by-year growth breakdown.

Simple Interest Calculator | I=PRT

Calculate simple interest using I = P × R × T formula.

Loan Payment Calculator

Calculate monthly loan payments, total interest, and amortization.

Tip Calculator | Split Bill

Calculate tip amount, total bill, and split between multiple people.

Mortgage Calculator | Monthly Payment

Calculate monthly mortgage payments, total interest, and amortization schedule.

ROI Calculator | Return on Investment

Calculate return on investment percentage from cost and revenue.

Currency Converter | Live Exchange Rates

Convert between 35 world currencies with live daily exchange rates. Shows mid-market rates, rate table, and popular pairs.

Depreciation Calculator | SL, DDB & SYD

Calculate annual depreciation and full amortization schedules using straight-line, double declining balance, and sum-of-years-digits methods. Includes book value chart and method comparison.

Income Tax Calculator | US 2024

Estimate your income tax based on US federal tax brackets (2024). Calculate effective tax rate.

Break-Even Calculator

Calculate the break-even point in units and revenue from fixed costs, variable costs, and selling price. Includes contribution margin, CM ratio, safety margin, operating leverage, target profit planning, and a visual break-even chart.

Retirement Savings Calculator

Project how much you will have at retirement based on savings rate, return, and time horizon.

Inflation Calculator | Purchasing Power

Calculate the purchasing power of money over time using historical or custom inflation rates.

NPV Calculator | Net Present Value

Calculate the net present value (NPV) and profitability index of an investment.

Debt Payoff Calculator | Credit Card & Loan

Calculate how long to pay off any debt and total interest paid. Includes amortization schedule, extra payment comparison, and find-required-payment mode for credit cards and loans.

Savings Goal Calculator

Calculate how long to reach a savings goal or the monthly contribution needed.

Salary to Hourly Calculator

Convert annual salary to hourly, daily, weekly, and monthly rates.

Hourly to Salary Calculator | Advanced Pay Converter

Convert any hourly wage to annual salary, monthly, bi-weekly, weekly, and daily pay. Includes benefits valuation, contractor vs employee cost comparison, gross-to-net tax estimate, multi-currency support, and PDF/CSV export.

GST / VAT Calculator | Add, Remove & Multi-Item

Add or remove GST/VAT from any price. Multi-item invoices with individual rates. Country presets for Australia, UK, India, Canada, and EU. 6 currencies supported.

Bill Splitter | Tip & Split

Split a restaurant bill with custom tip percentage and divide equally among any number of people.

Annuity Calculator | PV, FV, Payment, Term & Perpetuity

Calculate present value, future value, required payment, or term for ordinary annuities and annuities-due. Includes perpetuity mode, step-by-step working, and a year-by-year growth or amortization schedule.

APR Calculator | True Cost of Any Loan

Calculate the Annual Percentage Rate (APR) and Effective Annual Rate (EAR) for any loan. Accounts for upfront fees, shows step-by-step Newton-Raphson solution, and compares two loan offers side by side.

Fuel Cost Calculator | Trip Cost & CO2

Calculate trip fuel cost from distance, fuel efficiency, and price per litre. Supports L/100km, km/L, MPG US/UK, six currencies, CO2 estimate, and step-by-step working.

Auto Loan Calculator | Monthly Car Payment

Calculate your monthly car loan payment with down payment, trade-in, sales tax, and fees. Includes a full amortization schedule, rate sensitivity table, down payment impact analysis, and side-by-side loan comparison.

Investment Calculator | Growth, Returns & Retirement

Project long-term investment growth with monthly contributions and lump-sum inputs. Compare conservative, moderate, and aggressive return scenarios, see inflation-adjusted value, and estimate retirement income using the 4% withdrawal rule.

Net Worth Calculator | Assets, Debts & Financial Health

Calculate your net worth by listing all assets and liabilities. See how you compare to Federal Reserve age benchmarks, check your debt-to-asset ratio, and find your financial independence number.

Budget Calculator | 50/30/20 Rule & Monthly Planning

Build a monthly budget and compare your actual spending to the 50/30/20 rule. Track needs, wants, and savings against recommended targets, check emergency fund readiness, and see your personal savings rate.

Rent vs Buy Calculator | True Cost Comparison

Compare the true total cost of renting vs buying over any time horizon. Includes opportunity cost of the down payment, equity buildup, home appreciation, rent inflation, and break-even year.

Paycheck Calculator | Net Pay & Tax Withholding

Calculate your exact take-home pay after federal income tax, FICA, state taxes, and pre-tax deductions like 401(k) and health insurance. Supports all 50 states and all filing statuses.

Home Affordability Calculator | Max Price & DTI

Find the maximum home price you can afford based on income, debts, and down payment using the 28/36 DTI rule and FHA 43% maximum. Includes PMI estimate and PITI breakdown.

Student Loan Calculator | Repayment Plans & PSLF

Compare all federal student loan repayment plans (Standard, Graduated, Extended, IBR, PAYE, SAVE) with full IDR calculations, PSLF tracker, and private refinancing comparison.

Mortgage Refinance Calculator | Break-Even & Savings

Calculate your monthly savings, break-even month, and cumulative net savings from refinancing. Supports rate-term and cash-out refinancing with closing cost analysis.

CD Calculator | APY, Compounding & Early Withdrawal

Calculate Certificate of Deposit returns with APY, compounding frequency, early withdrawal penalty, and inflation-adjusted real return. Includes a 5-rung CD ladder builder.

Capital Gains Tax Calculator | 2024 Federal & State

Calculate federal and state capital gains tax on investments using 2024 LTCG brackets, NIIT (IRC § 1411), and all 50 states. Includes tax-loss harvesting scenario and holding period analysis.

Car Lease vs Buy Calculator | True Cost Comparison

Compare the true cost of leasing vs buying a car. Calculates lease payment from money factor and residual, total cost over the term, and equity advantage of buying.

College Savings Calculator | 529 & Tuition Projection

Project 4-year college costs with tuition inflation, calculate 529 savings growth, and find the monthly contribution needed to cover 50%–100% of projected costs.

FIRE Calculator | Financial Independence Number

Calculate your FIRE number using the 4% safe withdrawal rate, find your months to financial independence, Coast FIRE number, and see how savings rate affects your timeline.

Dividend Calculator | DRIP Returns & Yield on Cost

Project dividend income with DRIP reinvestment, dividend growth rate, and price appreciation over time. Compare reinvesting vs. taking cash and see yield on cost by year.

Social Security Calculator | Claiming Age & Benefits

Estimate your Social Security benefit at 62, FRA, and 70 using the 2024 PIA formula with bend points. Find your break-even age, compare claiming strategies, and calculate spousal benefits.

RMD Calculator | Required Minimum Distribution 2024

Calculate your Required Minimum Distribution (RMD) using the IRS Uniform Lifetime Table (2022 update). Includes SECURE 2.0 rules, 10-year projection, and penalty for missed RMDs.

401(k) & Roth IRA Calculator

Compare traditional 401(k) and Roth IRA contributions side by side. Project tax-deferred vs. tax-free growth, estimate employer match impact, and find the breakeven tax rate to decide which account wins.

Bond Price Calculator | YTM, Duration & Convexity

Calculate bond price from yield to maturity, coupon rate, and maturity. Find YTM from price, compute Macaulay and modified duration, convexity, and accrued interest for clean vs dirty price.

Dollar-Cost Averaging Calculator | DCA Returns

Simulate dollar-cost averaging vs. lump-sum investing over any period. Compare average cost per share, total invested, portfolio value, and risk-adjusted returns across market scenarios.

Emergency Fund Calculator | Target & Savings Plan

Calculate your ideal emergency fund size based on monthly expenses, job stability, and household risk. Get a month-by-month savings plan and see how much interest you could earn in a HYSA.

Rental Property Calculator | Cap Rate & Cash Flow

Analyze rental property returns with cap rate, cash-on-cash return, gross rent multiplier, NOI, and projected 10-year equity. Compare financing scenarios and calculate the 50% and 1% rules.

Options Pricing Calculator | Black-Scholes & Greeks

Price European call and put options using the Black-Scholes model. Calculate all five Greeks (Delta, Gamma, Theta, Vega, Rho), implied volatility, intrinsic vs. time value, and breakeven price.

Credit Card Payoff Calculator | Debt-Free Date

Calculate exactly when you will pay off your credit card debt and how much interest you will pay. Compare minimum payments vs fixed amounts, model avalanche and snowball strategies, and see how extra payments save you money.

Amortization Calculator | Full Payment Schedule

Generate a complete month-by-month amortization schedule for any loan. See exactly how much principal and interest you pay each month, your remaining balance, and the total cost of the loan over its full term.

CAGR Calculator | Compound Annual Growth Rate

Calculate compound annual growth rate (CAGR) from a beginning value, ending value, and number of years. Reverse-solve for required end value or time horizon. Compare CAGR across multiple investments side by side.

Present Value Calculator | PV of Future Cash Flows

Calculate the present value of a future lump sum or annuity stream. Discount future money back to today using any rate. Compare PV of multiple cash flows and understand the time value of money with step-by-step working.

Portfolio Rebalancer | Target Allocation & Drift Analysis

Rebalance your investment portfolio to target allocations. Analyze drift, generate buy/sell trade recommendations, and model cash additions. Supports up to 15 assets with a visual allocation chart and tax-lot awareness.

DRIP Calculator | Dividend Reinvestment & Compound Growth

Project dividend reinvestment plan (DRIP) growth over time. Enter shares, price, and yield; model dividend growth and price appreciation; see year-by-year shares accumulated, income, and total portfolio value with yield-on-cost progression.

Freelance Rate Calculator | Hourly & Project Pricing

Calculate the minimum hourly rate you must charge as a freelancer to hit your income goals. Accounts for taxes, billable vs non-billable hours, overhead, benefits gap, and vacation. Output includes day, week, and project rates with a breakeven analysis.

Mortgage Points Calculator | Discount Points Break-Even Analysis

Determine whether buying mortgage discount points makes financial sense. Compare up to four scenarios (0, 0.5, 1, 2 points) with monthly payment reduction, total interest savings, and exact break-even month. Includes a sell-before-break-even analysis.

CD Ladder Calculator | Multi-Rung Certificate of Deposit Strategy

Build a certificate of deposit ladder with 2 to 6 rungs, each with its own APY and term. See a complete maturity schedule, rolling reinvestment projections, total interest earned per rung, and how the ladder compares against putting everything in one CD.

Meeting Cost Calculator | Real-Time Meeting Expense Tracker

Calculate the true monetary cost of any meeting with a live ticking timer. Add multiple attendees with individual annual salaries, see the cost climb in real time, get a per-minute breakdown, and estimate how much your weekly recurring meetings cost the organization per year.

Loan Comparison Calculator | Compare 3 Loans Side by Side

Compare up to three loans simultaneously. Enter principal, interest rate, and term for each loan to see monthly payments, total interest paid, total cost, and a year-by-year remaining balance. Automatically ranks loans by cheapest total cost and highlights the best option.

Debt-to-Income Calculator | DTI Ratio & Mortgage Qualification

Calculate your front-end and back-end debt-to-income (DTI) ratios for mortgage and loan qualification. Enter all monthly debts and gross income to see whether you meet Conventional, FHA, and VA lending guidelines. Includes a reverse calculator to find your maximum loan amount.

Savings Withdrawal Calculator | How Long Will My Money Last?

Find out exactly how long your savings will last at any withdrawal rate, investment return, and inflation rate. Model the 4% rule, add annual contributions during drawdown, compare three return scenarios side by side, and use the sustainable rate finder to calculate the maximum withdrawal that never depletes savings over 30 years.

Closing Cost Calculator | Buyer & Seller Real Estate Fees

Estimate all closing costs for a home purchase or sale. Buyer side covers loan origination, title insurance, appraisal, prepaid interest, escrow reserves, and transfer taxes. Seller side shows net proceeds after agent commissions, payoff, and all settlement charges.

Overtime Pay Calculator | Hourly, OT & Double-Time Gross Pay

Calculate gross pay including regular, overtime (1.5×), and double-time (2×) earnings for any pay period. Supports FLSA federal rules, California daily OT rules, and custom multipliers. Shows a complete pay breakdown by rate type with annual projection.

Crypto Profit Calculator | Cryptocurrency P&L, ROI & Tax Estimator

Calculate cryptocurrency profit, loss, and ROI for any coin or token. Enter buy and sell prices with quantity to see net gain/loss, percentage return, short-term vs long-term capital gains tax estimate, and break-even price. Supports dollar-cost averaging across multiple entries.

HSA Calculator | Tax Savings, Contribution Limits & Investment Growth

Maximize your Health Savings Account with detailed tax savings across federal, state, and FICA contributions. Covers 2024–2025 IRS limits, age-55 catch-up amounts, investment growth projection, and a side-by-side comparison of spending HSA funds now versus investing for retirement.

Salary Negotiation Calculator | Compare Total Compensation Packages

Compare two job offers side-by-side on total compensation — not just base salary. Quantifies the dollar value of 401k match, health insurance, PTO days, remote work savings, equity/RSU, signing bonus, and annual raise trajectory. Shows true yearly and lifetime earnings difference.

Economic Order Quantity Calculator | EOQ, Reorder Point & Safety Stock

Calculate the optimal Economic Order Quantity (EOQ) using the Wilson formula √(2DS/H), together with reorder point (ROP), safety stock, cycle stock, average inventory, annual ordering cost, annual holding cost, and total inventory cost.

IRR Calculator | Internal Rate of Return, MIRR & Payback Period

Calculate the Internal Rate of Return (IRR) and Modified IRR (MIRR) for a series of up to 20 cash flows using the Newton-Raphson iterative method. Also computes net present value at any discount rate, discounted payback period, and profitability index.

GCD & LCM Calculator | Up to 10 Numbers

Find the GCD and LCM of up to 10 integers using the Euclidean algorithm. Shows prime factorization, divisibility check, and full step-by-step working.

Prime Factorization Calculator

Find the prime factorization of any positive integer and check primality.

Factorial Calculator | n!, n!! & Derangements

Calculate standard factorial (n!), double factorial (n!!), and subfactorial (!n / derangements) with exact BigInt arithmetic, scientific notation, digit count, trailing zeros, Stirling approximation, and step-by-step working.

Fibonacci Calculator | F(n), Sequence & Check

Find any Fibonacci number F(n) with exact BigInt arithmetic up to F(10000), generate sequences with golden ratio convergence, and check whether any integer is a Fibonacci number using the algebraic 5n²±4 perfect-square test.

Prime Number Checker

Check if any number is prime using an optimized trial division algorithm. Also lists factors.

Perfect Number Checker

Check if a number is perfect, abundant, or deficient and find all its proper divisors.

Roman Numeral Converter

Convert between Arabic numbers and Roman numerals (I, V, X, L, C, D, M).

Number Sequence Calculator

Find the nth term of arithmetic, geometric, and other common sequences.

Digital Root Calculator

Calculate the digital root (iterated sum of digits), additive persistence, Harshad check, and multiplicative digital root for any integer up to 300 digits.

Modular Arithmetic Calculator | Modular Inverse, CRT & Power Mod

Perform all core modular arithmetic operations with full step-by-step working. Computes (a op b) mod n, finds modular inverses using the Extended Euclidean Algorithm, solves two-congruence systems via the Chinese Remainder Theorem, and computes modular exponentiation with repeated squaring.

Continued Fraction Calculator | Convergents & Best Rational Approximations

Convert any decimal or fraction to its continued fraction expansion [a₀; a₁, a₂, ...] with up to 12 terms. Computes the full convergent table showing the best rational approximations at each step, the approximation error, and evaluates any given continued fraction back to its decimal value.

Big Number Calculator | Arbitrary Precision Arithmetic

Perform exact arithmetic on integers of any size using JavaScript BigInt. Supports addition, subtraction, multiplication, exponentiation, factorial, GCD, LCM, and modular arithmetic with no floating-point rounding errors. Displays the number of digits in the result and checks whether the result is prime using the Miller-Rabin primality test.

Euler's Totient Calculator | φ(n), Coprimes & Euler's Theorem

Compute Euler's totient function φ(n) — the count of integers from 1 to n that are coprime with n. Shows the prime factorization method, lists all coprimes for n ≤ 500, demonstrates multiplicativity φ(mn) = φ(m)φ(n), and verifies Euler's theorem aᵠ⁽ⁿ⁾ ≡ 1 (mod n) for any chosen a.

Catalan Number Calculator | Sequence, Formula & Applications

Compute Catalan numbers Cₙ up to n = 30 using exact arithmetic. Shows the closed-form formula C(2n,n)/(n+1), the recursive formula, and a table of all values. Explains applications: number of valid bracket sequences, binary tree shapes, convex polygon triangulations, mountain ranges, and ballot paths.

Collatz Sequence Calculator | 3n+1 Conjecture, Stopping Time & Path

Explore the Collatz conjecture (3n+1 problem) for any positive integer. Computes the complete sequence path, stopping time, total steps, peak value, and odd-step count. Visualizes the trajectory and lets you compare stopping times across a range of starting values.

Chinese Remainder Theorem Calculator | Simultaneous Congruences Solver

Solve a system of simultaneous congruences x ≡ a₁ (mod m₁), x ≡ a₂ (mod m₂), … using the Chinese Remainder Theorem. Applies Garner's algorithm for pairwise-coprime moduli and shows step-by-step Bézout coefficient computation.

Velocity Calculator | Speed & Time

Calculate velocity, distance, or time using v = d/t.

Acceleration Calculator | Kinematic Equations

Solve for acceleration, final velocity, initial velocity, time, or displacement using the five kinematic equations. Includes g-force conversion and step-by-step working.

Force Calculator | Newton's Second Law F = ma

Calculate force, mass, or acceleration using Newton's Second Law (F = ma). Solve for any variable with multi-unit support (N, kN, lbf, kgf, kg, lb, slug), preset real-world scenarios, g-force output, and gravitational weight on seven Solar System bodies.

Projectile Motion Calculator

Calculate range, max height, time of flight, and trajectory.

Work & Energy Calculator

Calculate work done, kinetic energy, potential energy, and power.

Momentum Calculator | p=mv

Calculate momentum, impulse, and solve collision problems.

Ohm's Law Calculator, V=IR

Calculate voltage, current, resistance, or power using Ohm's law.

Wave Calculator | Wavelength & Frequency

Calculate wavelength, frequency, period, and wave speed.

Gravity Calculator | Free Fall, Force & Escape

Calculate free fall height, time, and velocity. Compute gravitational force with Newton's law. Find surface gravity and escape velocity for any planet. NASA planet data included.

Ideal Gas Law Calculator | PV=nRT

Solve PV = nRT for any unknown variable.

Friction Calculator | Static, Kinetic & Inclined Plane

Calculate static and kinetic friction forces, find the normal force or coefficient, and solve inclined plane problems. Includes 11 material presets with published μ values.

Pendulum Calculator | Period & Frequency

Calculate the period, frequency, and length of a simple pendulum.

Spring Constant Calculator | Hooke's Law

Calculate spring constant, force, or displacement using Hooke's law (F = kx).

Coulomb's Law Calculator, Electrostatic Force

Calculate electrostatic force, charge, or distance using Coulomb's Law F = kq₁q₂/r². Supports multiple units, dielectric media, and solve-for-any-variable mode.

Capacitance Calculator | Q=CV, Energy & RC Circuits

Calculate charge, voltage, energy stored, series/parallel equivalents, and RC time constants for capacitors. Multi-unit support with circuit diagrams.

Thermal Expansion Calculator

Calculate linear and volumetric thermal expansion of materials.

Pressure Calculator | P=F/A

Calculate pressure from force and area, convert pressure units, and compute fluid pressure.

Density Calculator | ρ = m/V, Mass & Volume

Calculate density, mass, or volume using ρ = m/V. Supports multi-unit inputs, 40+ material presets, specific gravity, buoyancy check, and full unit conversion table.

Decibel Calculator | dB, Power & Sound Level

Convert between decibels, power ratios, and amplitude ratios. Combine multiple sound sources, compute distance attenuation, and see NIOSH hearing safety limits with an SPL reference meter.

Doppler Effect Calculator | Sound & Light

Calculate observed frequency shift for sound and light using classical and relativistic Doppler formulas. Includes medium presets, direction toggles, semitone output, and redshift z.

Centripetal Force Calculator

Solve for centripetal force, mass, velocity, or radius for circular motion. Supports linear velocity, angular velocity, frequency, and period. Includes 5 real-world presets, g-force output, and circular motion diagram.

Torque Calculator | τ = rF sin(θ)

Calculate torque from force, distance, and angle of application.

Kinetic Energy Calculator | KE=½mv²

Calculate translational and rotational kinetic energy.

Potential Energy Calculator | PE=mgh

Calculate gravitational potential energy (mgh) and elastic potential energy (½kx²).

Snell's Law Calculator, Refraction

Calculate refraction angles and critical angles for light passing between media.

Lens Equation Calculator | Optics

Calculate focal length, object distance, image distance, and magnification for thin lenses.

Half-Life Calculator | Radioactive Decay

Calculate remaining quantity, time elapsed, half-life, and decay constant using the exponential decay formula. Supports 4 modes, decay table, and isotope reference.

Escape Velocity Calculator | Planets & Stars

Calculate escape velocity, orbital speed, surface gravity, Schwarzschild radius, and orbital period for any planet, star, or celestial body. Solve for velocity, mass, or radius with solar system presets.

Buoyancy Calculator | Archimedes

Calculate buoyant force using Archimedes' principle (F = ρVg). Determines float or sink status, fraction submerged, apparent weight, net force, and operating leverage across Earth, Moon, Mars, and Jupiter gravity. Includes fluid and material density presets.

Heat Transfer Calculator | Conduction, Convection & Radiation

Calculate heat transfer by Fourier conduction, Newton convection, Stefan-Boltzmann radiation, or Q=mcΔT sensible heat. Material presets, NIST constants, step-by-step working.

Electric Power Calculator | P=VI, V²/R & I²R

Calculate electric power from any two of voltage, current, and resistance. Includes energy consumption in kWh and electricity cost estimation with preset appliances.

Magnetic Force Calculator | Lorentz

Calculate the magnetic force on a moving charge (Lorentz force) F = qvB sin(θ).

Resistor Color Code Calculator

Decode 4-band and 5-band resistor color codes to find resistance and tolerance.

Blackbody Radiation Calculator

Calculate peak wavelength, total radiated power per unit area, photon energy, and Planck spectrum for any temperature and emissivity. Visual spectrum chart included.

Reynolds Number Calculator

Calculate the Reynolds number to determine laminar or turbulent fluid flow.

Electric Field Calculator | Point Charge & Plates

Calculate electric field strength from point charges (E = kQ/r²), parallel plates (E = V/d), and electrostatic force (F = qE) with unit conversion and air-breakdown indicator.

Sound Intensity Calculator | dB

Calculate sound intensity level in dB from intensity, and convert between intensity and dB.

Specific Gravity Calculator

Calculate specific gravity, relative density, and compare material density to water.

Wave Speed Calculator | v = fλ

Calculate wave speed, frequency, wavelength, or period using v = fλ. Supports sound, light, and all wave types across different media with unit conversion.

Kinematics Calculator | SUVAT Equations

Solve all five SUVAT kinematic equations for displacement, initial velocity, final velocity, acceleration, and time. Enter any three known values and instantly solve for the remaining two.

Energy Calculator | KE, PE, Thermal & Electrical

Calculate kinetic energy (½mv²), gravitational PE (mgh), elastic PE (½kx²), thermal energy (mcΔT), and electrical energy (Pt). Convert between energy forms and units.

Specific Heat Calculator | Q = mcΔT Calorimetry

Calculate heat energy (Q), mass (m), specific heat capacity (c), or temperature change (ΔT) using Q = mcΔT. Solve any unknown, includes a reference table of 30+ common substances, and supports calorimetry problems with heat exchange between objects.

Combined Gas Law Calculator | P₁V₁/T₁ = P₂V₂/T₂

Solve the combined gas law for any unknown pressure, volume, or temperature. Also handles Boyle's Law (constant T), Charles's Law (constant P), and Gay-Lussac's Law (constant V) as special cases. Supports all major pressure and volume units.

Wind Chill Calculator | Feels-Like Temperature & Frostbite Risk

Calculate wind chill temperature using the official NWS formula for any air temperature and wind speed combination. Shows how cold it actually feels, frostbite risk time estimates at 30, 10, and 5 minutes, safety guidance, and a wind chill reference chart.

Heat Index Calculator | Feels-Like Temperature & Heat Safety Levels

Calculate the heat index (feels-like temperature) from air temperature and relative humidity using the official NWS Rothfusz regression equation. Shows heat safety category — Caution through Extreme Danger — with practical cooling recommendations and heat illness warning signs.

Thermodynamics Calculator | ΔG, ΔH, ΔS, Hess's Law & Carnot

Compute Gibbs free energy ΔG = ΔH − TΔS for chemical reactions at any temperature. Determines spontaneity, finds the crossover temperature where ΔG = 0, applies Hess's law to combine up to three reactions, and calculates Carnot engine efficiency, heat pump COP, and refrigerator COP.

Special Relativity Calculator | Time Dilation, Length Contraction & Velocity Addition

Compute relativistic effects at any velocity from 0 to c: Lorentz factor γ, time dilation Δt, length contraction L, relativistic momentum p, kinetic energy Ek, total energy E = mc², and relativistic velocity addition. Enter velocity as a fraction of c.

Photoelectric Effect Calculator | Work Function, Threshold Frequency & Stopping Voltage

Apply Einstein's photoelectric equation E = hf − φ to compute work function (φ), threshold frequency (f₀), threshold wavelength (λ₀), stopping voltage (Vs), and photoelectron kinetic energy. Includes a table of work functions for 15 common metals.

Orbital Mechanics Calculator | Period, Velocity & Altitude for Satellites

Compute orbital period, circular velocity, escape speed, orbital radius, and altitude for satellites around Earth, Moon, Mars, Jupiter, or custom bodies. Supports Hohmann transfer delta-v calculation between two circular orbits. Shows orbital energy and angular momentum.

Tidal Force Calculator | Tidal Acceleration, Differential Gravity & Roche Limit

Compute tidal acceleration, differential gravitational force, tidal deformation, and the Roche limit for any planet-moon or star-planet system. Includes data presets for Earth-Moon, Sun-Earth, Jupiter-Io, and Saturn-Titan, plus custom mass and distance inputs.

Mach Number Calculator | Subsonic, Transonic & Supersonic Flow Properties

Compute Mach number, dynamic pressure, stagnation (total) temperature, stagnation pressure, and speed of sound for subsonic, transonic, and supersonic flows. Supports ISA standard atmosphere from sea level to 50 km altitude with ambient condition lookup.

Nuclear Binding Energy Calculator | Mass Defect, BE/A & Bethe-Weizsäcker Formula

Compute nuclear binding energy, mass defect (Δm), binding energy per nucleon (BE/A), and Q-value for over 100 common isotopes using CODATA atomic mass data. Compares stability across isotopes and estimates BE using the semi-empirical Bethe-Weizsäcker formula.

Matrix Determinant Calculator

Calculate the determinant of 2×2 and 3×3 matrices.

Matrix Multiplication Calculator

Multiply two matrices together with step-by-step dot products.

Vector Calculator | Dot & Cross Product

Add, subtract, find dot product, cross product, and magnitude of vectors.

Matrix Inverse Calculator

Calculate the inverse of a 2×2 or 3×3 matrix with step-by-step elimination.

Eigenvalue & Eigenvector Calculator | 2×2 & 3×3

Calculate eigenvalues and eigenvectors for 2×2 and 3×3 matrices. Shows characteristic polynomial, eigenvectors, diagonalization, matrix properties, and step-by-step working.

Matrix Transpose Calculator

Transpose matrices of any size by swapping rows and columns.

Matrix RREF Calculator

Reduce any matrix to Row Reduced Echelon Form (RREF) using Gauss-Jordan elimination. Shows pivot positions, rank, and step-by-step row operations.

Matrix Calculator | Add, Multiply & Invert

Perform matrix addition, subtraction, multiplication, transposition, and find the determinant and inverse for matrices up to 4×4. Step-by-step working shown for all operations.

Cross Product Calculator | 3D Vector a × b

Calculate the cross product of two 3D vectors, find the resulting vector's magnitude and unit vector, verify orthogonality to both inputs, and compute the area of the parallelogram they span. Full determinant working shown with angle between vectors.

Matrix LU Decomposition | Solve Ax=b, Determinant & Step-by-Step

Decompose any 2×2, 3×3, or 4×4 matrix A into lower-triangular L and upper-triangular U using Doolittle's method. Shows each elimination step, uses LU to solve Ax=b via forward and back substitution, computes the determinant as the product of U's diagonal, and verifies A=LU.

Vector Projection Calculator | Projection, Decomposition & Gram-Schmidt

Compute the projection of vector u onto v in 2D or 3D, decompose u into parallel and perpendicular components, find the angle between vectors, and orthogonalize up to three vectors using the Gram-Schmidt process. Computes unit vectors, magnitudes, dot products, and scalar projections with full working.

Gram-Schmidt Calculator | Orthogonalization, Orthonormal Basis & QR Decomposition

Apply the Gram-Schmidt process to 2–4 linearly independent vectors in R²–R⁴ to produce an orthogonal basis and orthonormal basis. Displays the full QR decomposition Q·R = A and verifies orthogonality via dot products.

Combination Calculator | nCr & n Choose r

Calculate C(n,r) combinations without repetition, C̄(n,r) with repetition, P(n,r) permutations, and nʳ, all in one tool. Supports BigInt exact arithmetic for large n, step-by-step working, Pascal's triangle, combination listing, and session persistence.

Permutation Calculator | nPr

Calculate the number of permutations where order matters.

Boolean Algebra Calculator

Evaluate Boolean expressions with AND, OR, NOT, XOR, NAND, NOR, XNOR, implication, and biconditional. Generates truth tables for up to 4 variables with SOP, POS canonical forms, Σm/ΠM notation, and equivalence checking.

Combinations with Repetition | Stars & Bars

Calculate multiset combinations C̄(n,r) = C(n+r−1,r) where repetition is allowed. Features stars & bars visualization, step-by-step working, multiset listing, all four combinatorial variants, BigInt exact arithmetic, and session persistence.

Pascal's Triangle Calculator

Generate Pascal's triangle up to any row and expand (a + b)ⁿ using the binomial theorem. Shows all coefficients and the full polynomial expansion.

Set Theory Calculator | Union, Intersection, Complement & Venn Diagram

Define up to three sets A, B, C with any elements and compute all standard set operations: union, intersection, difference, symmetric difference, complement, Cartesian product, and power set. Displays a membership table, text Venn diagram, cardinality, and subset relationships.

Recurrence Relation Solver | Closed-Form Solution & Sequence Generator

Solve second-order linear homogeneous recurrence relations aₙ = p·aₙ₋₁ + q·aₙ₋₂ with initial conditions. Finds the characteristic equation, analyzes roots (distinct real, repeated, complex conjugate), builds the closed-form general solution, and generates the first N terms.

Sequence Analyzer | Detect Pattern, nth Term & Generate Terms

Enter any numerical sequence and automatically detect whether it is arithmetic, geometric, quadratic, cubic, Fibonacci-type, or power-based. Finds the closed-form nth term formula, builds a complete difference table at every order, generates the next N terms, and computes partial sums.

Advanced Combinatorics | Derangements, Bell, Catalan & Stirling Numbers

Compute advanced counting numbers in one place: derangements D(n), Bell numbers B(n), Catalan numbers C(n), Stirling numbers of the second kind S(n,k), multinomial coefficients, and stars-and-bars distributions. Each result includes the definition, step-by-step working, and a real-world application.

Truth Table Generator | Boolean Expression Evaluator

Generate complete truth tables for any Boolean expression with up to 4 variables. Supports AND, OR, NOT, XOR, NAND, NOR, and XNOR operators. Automatically identifies tautologies, contradictions, and contingencies, and derives the canonical DNF and CNF forms with minterm and maxterm listings.

Permutation Group Calculator | Cycle Notation, Composition & Order

Work with permutations in cycle notation. Compose two permutations, compute the inverse, raise a permutation to any power, and find its order. Displays each permutation in two-line notation, full cycle decomposition, sign (even or odd), and supports the symmetric group Sₙ for n up to 8.

Markov Chain Calculator | Steady State, n-Step & Absorbing States

Analyze discrete-time Markov chains with up to 4 states. Enter the transition probability matrix and compute: the n-step transition matrix (matrix multiplication), the steady-state (stationary) distribution by power iteration, absorption probabilities for absorbing states, and the expected return time for each state.

Game Theory Calculator | Nash Equilibria, Minimax & Dominant Strategies

Analyze 2×2 and 3×3 two-player strategic games. Finds all pure Nash equilibria by best-response check, computes mixed Nash equilibria for 2×2 games, identifies strictly and weakly dominant strategies, determines minimax and maximin values for zero-sum games, and classifies the game type.

Quartic Equation Solver | ax⁴+bx³+cx²+dx+e=0

Solve quartic equations (ax⁴+bx³+cx²+dx+e=0) and find all four roots — real and complex — with step-by-step working, factored form, and root verification.

3-Variable System of Equations Solver | 3×3

Solve systems of three linear equations with three unknowns using Gaussian elimination. Handles unique, no solution, and infinite solution cases with full step-by-step row operations.

Partial Fraction Decomposition Calculator

Decompose rational expressions P(x)/Q(x) into partial fractions. Handles linear, repeated linear, and irreducible quadratic denominator factors with step-by-step coefficient solving.

Piecewise Function Calculator & Evaluator

Define piecewise functions with up to 4 pieces, evaluate at any x, check continuity at breakpoints, identify discontinuity types, and view a table of values. Supports standard math expressions.

Exponential & Logarithmic Equation Solver

Solve all standard exponential and logarithmic equations — a·bˣ=c, eˣ=c, log₂(x)=c, ln(ax+b)=c, and quadratic-in-exponential forms — with complete step-by-step algebraic working.

Discrete Fourier Transform (DFT) Calculator | Spectrum Analysis

Compute the Discrete Fourier Transform of any signal sequence of up to 16 samples. Displays each frequency bin's magnitude, phase (radians and degrees), and real and imaginary components in a full results table. Computes the Inverse DFT to verify signal reconstruction and includes common signal presets.

Simplex Method Calculator | Linear Programming Step-by-Step

Solve two-variable linear programming problems with the simplex method. Enter the objective function (maximize or minimize) and up to four inequality constraints. Displays the initial tableau, each pivot operation with entering and leaving variables, and the final optimal solution with all basic feasible solutions listed.

Queuing Theory Calculator | M/M/1 & M/M/c Queue Metrics

Model M/M/1 (single-server) and M/M/c (multi-server) Poisson arrival queues. Computes server utilization ρ, average number in system L, average queue length Lq, mean system time W, mean wait time Wq, and probability P(n) of exactly n customers.

Equation Graph Generator | Plot y = f(x)

Plot up to 3 simultaneous y = f(x) equations on a shared axis. Supports polynomials, trig, logs, exponentials, and more. Download as PNG or copy to clipboard.

Parametric Curve Grapher | x(t) y(t)

Plot parametric curves defined by x(t) and y(t) and download the graph as PNG.

Polar Graph Generator | r(θ)

Plot polar equations r(θ) including roses, spirals, and limaçons. Download as PNG.

Bezier Curve Calculator | De Casteljau Algorithm & Curve Points

Compute quadratic and cubic Bezier curves using the De Casteljau algorithm. Enter control points, choose any parameter t ∈ [0, 1], and see every intermediate interpolation step. Generates a full table of (x, y) coordinates along the curve, computes the tangent vector, and shows the first and second derivative formulas.

Random Number Generator

Generate random integers or decimals within any range. Generate single or multiple numbers at once.

Random Password Generator

Generate strong, secure random passwords with custom length and character sets.

Dice Roller | D4 to D100 with Advantage

Roll any combination of dice including D4, D6, D8, D12, D20, D100, or fully custom sides. Supports advantage, disadvantage, drop-lowest, modifiers, probability distribution charts, and full roll history.

Random List Picker

Enter a list of items and randomly pick one or more. Perfect for decisions, giveaways, and selections.

Coin Flip Simulator | Heads or Tails Online

Free online coin flip simulator with animated flip, adjustable bias (0–100%), batch flipping up to 100,000 times, live statistics (z-score, chi-square, streak tracking), flip history grid, and session persistence. Demonstrates the law of large numbers in real time.

Random Color Generator | HEX, RGB

Generate random colors with HEX, RGB, and HSL values. Copy values instantly.

Lottery Number Generator

Generate one secure lottery ticket line for Powerball, Mega Millions, EuroJackpot, Viking Lotto, UK Lotto, or Irish Lotto with optional locks and saved tickets.

UUID Generator | UUID v4

Generate UUID v4 universally unique identifiers instantly. Generate single or bulk UUIDs.

Age Calculator | Exact Age, Milestones & Birthday Countdown

Calculate your exact age in years, months, days, hours, and minutes. Includes next birthday countdown, zodiac sign, Chinese zodiac, generation, and age milestones.

Date Difference Calculator | Days Between Two Dates

Calculate the exact number of calendar days, business days, weeks, months, and years between any two dates. Includes hours, minutes, seconds, leap year count, and inclusive/exclusive endpoint options.

Unix Timestamp Converter

Convert between Unix timestamps and human-readable dates. Supports seconds and milliseconds.

Day of Week Calculator | What Day Was Any Date?

Find the day of the week for any date, past, present, or future. Shows ISO week number, day of year, quarter, leap year status, zodiac sign, and a mini calendar view. Includes famous historical dates and day-offset shortcuts.

Work Hours Calculator | Time & Pay

Calculate total work hours between a start and end time, with optional break deductions.

Shift Schedule Creator | Automatic Shift Planner

Automatically generate weekly shift schedules for any team. Add workers, define shift types, set preferences and days-off constraints, then auto-generate a balanced calendar. Download as PDF or CSV.

Countdown Calculator | Days Until Any Event

Live countdown to any date with days, hours, minutes, seconds, progress bar, business days, and saved countdowns.

Time Duration Calculator

Add or subtract time durations. Convert hours, minutes, and seconds.

Business Days Calculator

Count working days between two dates, add or subtract business days to find deadlines, and run a countdown, with US & UK holiday presets, Mon–Fri/Sun–Thu/Mon–Sat work week options, and detailed breakdowns.

Time Zone Converter | World Clock & Meeting Planner

Convert times between any of 400+ time zones instantly. Compare multiple cities side by side, find the best meeting time across zones, and see DST change dates for every region.

Week Number Calculator | ISO Week & Year Calendar

Find the ISO week number for any date, list all weeks in a year, and calculate the date range for any given week. Supports ISO 8601 and US/North American week numbering conventions.

BMI Calculator | Body Mass Index & Healthy Weight

Calculate your BMI instantly with metric or imperial units. See your weight category, BMI Prime, Ponderal Index, healthy weight range, and personalised recommendations using WHO standards.

Calorie Calculator | TDEE & Weight Goals

Calculate daily calories using Mifflin-St Jeor, Harris-Benedict, or Katch-McArdle. Find your TDEE and set calorie targets for weight loss, maintenance, or muscle gain.

Body Fat Percentage Calculator | US Navy Method

Estimate body fat percentage using the US Navy circumference method. See lean mass, fat mass, body composition category, and a BMI-based comparison, in metric or imperial units.

Heart Rate Zone Calculator | 5 Training Zones

Calculate all 5 heart rate training zones using Max HR % or Karvonen method. Supports Standard, Tanaka, and Gellish formulas with visual zone bar chart.

Ideal Weight Calculator

Calculate ideal body weight using Devine, Robinson, Miller, and Hamwi formulas.

Water Intake Calculator | Hydration

Calculate your recommended daily water intake based on weight, activity level, and climate.

Running Pace Calculator

Calculate pace, speed, distance, or time for running, walking, and cycling activities.

Macronutrient Calculator | Macros

Calculate your daily protein, carbohydrate, and fat targets based on your TDEE and goals.

BMR Calculator | Basal Metabolic Rate & TDEE

Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas. Compare all three formulas and see daily calorie targets by goal.

Sleep Calculator | Best Bedtime

Calculate ideal bedtimes or wake-up times based on 90-minute sleep cycles. Find out when to sleep or wake to feel refreshed and avoid mid-cycle grogginess.

TDEE Calculator | Total Daily Energy Expenditure

Calculate your Total Daily Energy Expenditure (TDEE) with macro targets using the Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas. Set weight goals and see calorie targets for loss, maintenance, and gain.

Pregnancy Due Date Calculator | EDD & Milestones

Calculate your estimated due date from LMP, conception date, IVF transfer date, or ultrasound. Get week-by-week milestones, trimester dates, and key prenatal appointment windows.

Ovulation Calculator | Fertile Window & Cycle Tracking

Predict your fertile window and ovulation date from your cycle length and last period. Includes a 6-cycle fertility calendar, basal body temperature interpretation, and the LH surge timeline.

One-Rep Max Calculator | 1RM & Training Loads

Calculate your one-rep max using Epley, Brzycki, Lombardi, and O'Conner formulas. Get full training load percentages for 50–95% of 1RM and compare formulas to find your most accurate estimate.

Waist-to-Hip Ratio Calculator | WHR & Health Risk

Calculate your waist-to-hip ratio and see your WHO cardiovascular risk category. Includes waist-to-height ratio, a body shape comparison (apple vs. pear), and healthy range targets by sex and age.

VO2 Max Calculator | Fitness Level & Training Zones

Estimate VO2 max from a 1.5-mile run, Rockport walk test, resting heart rate, or submaximal cycle test. Get your fitness percentile, aerobic age, and five heart-rate training zones.

Caloric Deficit Calculator | Lose Weight Safely

Calculate the daily calorie deficit you need to reach your goal weight by a target date. Based on TDEE and BMR. Shows safe deficit ranges, recommended macro splits, estimated weekly loss, and how long to reach your goal at different deficit levels.

Calories Burned Calculator | 40+ Activities & MET

Calculate calories burned during any exercise or physical activity using MET values, body weight, and duration. Covers 40+ activities including running, cycling, swimming, weightlifting, and daily tasks. Compares net vs gross calories burned.

Lean Body Mass Calculator | LBM & Fat-Free Mass

Calculate lean body mass (LBM) using four clinical formulas: Boer, James, Hume, and Peters. Get fat mass, fat-free mass, skeletal muscle mass estimate, and ideal protein intake based on LBM. Used in medicine for drug dosing and fitness for muscle tracking.

Blood Pressure Calculator | AHA Categories & CVD Risk

Classify your blood pressure using 2017 AHA/ACC guidelines. Calculate pulse pressure, mean arterial pressure, and a 10-year cardiovascular risk estimate. Track multiple readings and see trend analysis.

Body Surface Area Calculator | BSA, IBW & Adjusted Weight

Calculate body surface area (BSA) using five clinical formulas: Mosteller, DuBois, Haycock, Gehan-George, and Boyd. Also computes Ideal Body Weight (Devine) and Adjusted Body Weight for drug dosing. Used in oncology, anesthesiology, and clinical pharmacy.

Blood Alcohol Content Calculator | BAC, Widmark Formula & Sobriety Timeline

Estimate blood alcohol content using the Widmark formula. Track drinks over time by type and strength, see a live BAC elimination curve, and calculate exactly when BAC drops below 0.08% (legal limit) and 0.00% (fully sober). Not a substitute for a breathalyzer.

Race Time Predictor | 5K, Half Marathon & Marathon Finish Time Calculator

Predict your finish time for any running race distance from one known performance using Riegel's formula. Covers 1 mile through 50K, includes equivalent training paces per distance, VDOT score, and personalized training zones for easy, tempo, interval, and repetition runs.

Period Calculator | Next Period Date, Fertile Window & Cycle Tracker

Predict your next period date, fertile window, and ovulation day from your last period and average cycle length. Displays a 6-month forward calendar with all cycle events color-coded. Supports irregular cycles with adjustable length range. Not for contraceptive use.

Intermittent Fasting Calculator | Eating Window, Protocols & Calorie Target

Set your intermittent fasting protocol (16:8, 18:6, 20:4, OMAD, 5:2, Warrior Diet), enter your eating window start time, and get exact eating/fasting start and end times plus a daily calorie target based on your TDEE and weight goal. Includes electrolyte guidance.

Dog Age Calculator | Dog Years to Human Years (Breed Size Adjusted)

Convert your dog's age to human years using a scientifically validated breed-size-adjusted formula — far more accurate than the outdated "multiply by 7" rule. Based on NIH epigenetic research, with life stage classification, milestone guide, and average lifespan by breed size.

Cat Age Calculator | Cat Years to Human Years (AAFP Life Stages)

Convert your cat's age to human years using AAFP feline life stage guidelines: kitten, junior, prime, mature, senior, and geriatric. See equivalent human age, life stage health priorities, estimated remaining lifespan, and indoor vs outdoor life expectancy comparison.

Smoking Cost Calculator | Financial Cost of Cigarettes & Quitting Savings

Calculate exactly how much you spend on cigarettes per day, month, and year — and see the compounding financial impact over 5, 10, and 20 years. Shows the investment equivalent of redirecting that spending and estimates the total spent since you started smoking.

Golf Handicap Calculator | USGA Handicap Index & Course Handicap

Calculate your official USGA Handicap Index from up to 20 recent scorecards. Enter gross score, course rating, and slope for each round to get handicap differentials, your index, and the resulting course handicap for any rated course. Supports 9-hole adjustments.

Swimming Pace Calculator | 100m Pace, Split Times & Lap Calculator

Calculate swimming pace per 100 meters or 100 yards, generate split times for any event distance, and estimate calorie burn based on stroke and weight. Supports 25m, 25-yard, and 50m pool lengths with a full lap-by-lap split table for competitive and fitness swimmers.

Bra Size Calculator | Band, Cup & Sister Size in US, UK & EU

Calculate your bra size from underbust and bust measurements in inches or centimeters. Outputs your band and cup size in US, UK, EU/European, French, and Australian sizing with sister size recommendations and a fit checklist to verify the result matches your body.

Baby Percentile Calculator | WHO & CDC Growth Charts 0–24 Months

Calculate your baby's weight, length/height, and head circumference percentiles using official WHO (0–24 months) and CDC growth charts. Plots each measurement on an interactive growth curve and explains what percentile ranges mean in pediatric context.

IV Drip Rate Calculator | Infusion Rate, Drops per Minute & Weight-Based Dose

Calculate intravenous infusion rate in mL/hr and drops/min for gravity drips (10, 15, 20, or 60 gtt/mL sets), weight-based dosing in mcg/kg/min or mg/kg/hr, total infusion time from volume and rate, and remaining infusion time from current volume.

GFR Calculator | CKD-EPI, MDRD & Cockcroft-Gault Creatinine Clearance

Estimate Glomerular Filtration Rate (GFR) using three validated equations: CKD-EPI 2021, MDRD 4-variable, and Cockcroft-Gault. Classifies CKD stage (G1–G5) per KDIGO 2022 guidelines, shows creatinine clearance, and flags dose-adjustment thresholds.

Molar Mass Calculator | Molecular Weight

Calculate the molar mass of common chemical elements and simple compounds.

Molarity Calculator | M = n/V

Calculate molarity, moles, or volume of solutions using M = n/V formula.

pH Calculator | pH, pOH & Ions

Calculate pH, pOH, [H⁺], and [OH⁻] concentrations for acids and bases.

Dilution Calculator | C₁V₁=C₂V₂

Solve any variable in C₁V₁ = C₂V₂ and generate serial dilution tables. Supports M, mM, µM, mg/mL, ppm and more.

Stoichiometry Calculator | Moles & Grams

Convert between moles and grams using molar mass. Calculate mass from moles and vice versa.

Periodic Table | Interactive Element Reference

Explore the full periodic table with detailed element data including atomic number, mass, electron configuration, electronegativity, density, melting point, and category. Search by name, symbol, or atomic number.

Percent Yield Calculator | Actual vs Theoretical Yield

Calculate percent yield, theoretical yield, or actual yield for any chemical reaction. Enter grams or moles, and get step-by-step stoichiometry working showing mole conversions, limiting reagent identification, and yield analysis.

Limiting Reagent Calculator | Find Limiting Reactant

Find the limiting reagent, excess reactant, and theoretical yield for any balanced chemical reaction. Enter masses or moles of two reactants, and get complete stoichiometric working with mole ratios and yield calculations.

Empirical Formula Calculator | From Mass or Percent

Find the empirical formula and molecular formula from mass percentages or grams of each element. Enter up to 6 elements, and see step-by-step mole calculations, ratio simplification, and molecular formula determination from molar mass.

Significant Figures Calculator | Count, Round & Arithmetic

Count significant figures in any number, round to N sig figs, and perform addition, subtraction, multiplication, and division with automatic sig fig rules applied. Supports scientific notation and explains which rule was used.

Henderson-Hasselbalch Calculator | Buffer pH

Calculate buffer pH using the Henderson-Hasselbalch equation: pH = pKa + log([A⁻]/[HA]). Solve for pH, pKa, or the acid/base ratio. Includes buffer capacity, weak base support, and common buffer presets for acetate, phosphate, TRIS, HEPES, and bicarbonate.

Chemical Equilibrium Calculator | ICE Table, Kc, Kp & Le Chatelier

Solve chemical equilibrium problems using ICE tables. Enter stoichiometry, equilibrium constant Kc or Kp, and initial concentrations to find equilibrium concentrations. Computes the reaction quotient Q, determines the direction of shift, and predicts Le Chatelier responses to perturbations.

Nernst Equation Calculator | Cell Potential at Non-Standard Conditions

Calculate electrochemical cell potential at any temperature and concentration using the Nernst equation E = E° − (RT/nF)ln Q. Supports concentration cell calculations (E° = 0), temperature variation, and solving for unknown ion concentrations when the measured potential is known.

Beer-Lambert Law Calculator | Absorbance, Transmittance & Concentration

Apply the Beer-Lambert law A = εlc to compute absorbance, percent transmittance, molar absorptivity (ε), path length, or concentration from any four known quantities. Supports multi-wavelength analysis and mixture concentration estimation.

Colligative Properties Calculator | Boiling Point Elevation & Freezing Point Depression

Compute the four colligative properties of solutions: boiling point elevation (ΔTb), freezing point depression (ΔTf), osmotic pressure (π), and vapor pressure lowering (ΔP). Supports electrolyte solutions via the van't Hoff i-factor for common solvents.

Arrhenius Equation Calculator | Activation Energy, Rate Constant & Half-Life

Compute the Arrhenius rate constant k, activation energy Ea, pre-exponential factor A, and reaction half-life using k = Ae^(−Ea/RT). Given two rate constants at two temperatures, back-calculates Ea. Shows temperature effect on rate with a comparison table.

Word Count Calculator

Count words, characters, sentences, paragraphs, and estimate reading time for any text.

Text Case Converter

Convert text to UPPERCASE, lowercase, Title Case, Sentence case, camelCase, or snake_case.

Base64 Encoder & Decoder

Encode text and files to Base64, decode Base64 strings, generate data URIs, and more. Supports URL-safe Base64, MIME line-wrap, and live processing.

Morse Code Converter

Convert text to Morse code and decode Morse code back to text.

ASCII & Unicode Value Calculator

Convert any character to ASCII decimal, hex, octal, binary, and UTF-8 bytes, or decode character codes back to text. Full ASCII table included.

Number to Words Converter

Convert any number (up to trillions) to its English word representation.

Reading Time Calculator | Words Per Minute Estimator

Estimate how long any text takes to read at average, fast, or slow reading speeds. Paste your text or enter word count, choose audience type, and get per-paragraph timing with speaking time comparison.

Cipher Calculator | Caesar, Vigenère, Atbash & Brute-Force Decoder

Encode and decode text with four classical ciphers: Caesar (any shift), Vigenère (any keyword), ROT13, and Atbash. Includes letter frequency analysis comparing plaintext and ciphertext distributions, and a brute-force Caesar cracker that shows all 26 possible decryptions ranked by English letter frequency score.

Color Harmony Calculator | Complementary, Triadic & Palette Generator

Enter any color as hex or RGB and instantly generate six classic color harmony palettes: complementary, analogous, triadic, split-complementary, tetradic, and square. Displays each color as a visual swatch with its hex, RGB, and HSL values. Includes contrast ratios for readability checks and a color blindness simulation overview.

Bitwise Calculator | AND, OR, XOR

Perform bitwise AND, OR, XOR, NOT, left shift, and right shift on 8/16/32-bit integers. Interactive bit toggle panel, colour-coded bit grid, multi-base output, and common bit manipulation patterns.

Binary Arithmetic Calculator

Add, subtract, multiply, and divide binary numbers with long-form carry/borrow visualization, column-by-column step table, multi-base output, and overflow detection.

Two's Complement Calculator

Convert integers to two's complement binary representation and back.

RGB to HEX Color Converter

Convert colors between RGB, HEX, and HSL formats instantly.

IP Subnet Calculator | CIDR

Calculate subnet mask, network address, broadcast address, and usable hosts for any CIDR.

Floating Point Converter | IEEE 754 Binary

Convert any decimal to its IEEE 754 32-bit and 64-bit binary representation, coloured bit display, field breakdown, special value detection, and hex-to-float reverse conversion. Runs entirely in your browser using JavaScript typed arrays.

Bandwidth Calculator | File Transfer Time & Speed

Calculate file transfer time from file size and connection speed. Convert between all bandwidth units (Mbps, GB, TB), estimate download/upload time, and see how many devices a connection can support simultaneously.

PPI Calculator | Pixel Density, Retina & Viewing Distance

Calculate pixels per inch (PPI) for any screen using resolution and diagonal size. Check retina/HiDPI thresholds, get optimal viewing distance recommendations, compare devices side by side, and convert between DPI, PPI, and DPCM.

Color Contrast Checker | WCAG AA & AAA Accessibility

Check color contrast ratios against WCAG 2.1 AA and AAA standards for normal and large text. Enter hex, RGB, or HSL colors; get relative luminance values; preview text on background; and get automatic suggestions to fix failing contrast.

Hash Generator | SHA-256, SHA-512, SHA-1 & HMAC Online Tool

Generate cryptographic hashes from text input or file upload using SHA-256, SHA-512, SHA-384, and SHA-1 algorithms via the browser's native Web Crypto API. Supports HMAC-SHA256 with a secret key, hex or Base64 output, and side-by-side hash comparison to verify file integrity.

Number Base Arithmetic | Add, Subtract, Multiply & Divide in Any Base

Perform addition, subtraction, multiplication, and division directly in any number base from 2 to 16 without first converting to decimal. Shows full carry and borrow steps column by column exactly as done by hand, with decimal cross-verification and support for binary, octal, and hexadecimal.

Binary Search Tree Calculator | Insert, Traverse & Balance Check

Build a binary search tree from any list of values. Visualizes the tree structure as ASCII art, computes all four traversals (inorder, preorder, postorder, level-order), reports tree height, minimum and maximum values, leaf count, and balance status. Supports search and delete operations with step-by-step explanation.

Huffman Coding Calculator | Prefix Codes & Compression Ratio

Build a Huffman tree from character frequencies. Enter a text string or a custom frequency table; the calculator constructs the optimal prefix-free binary code, displays each character's codeword, and reports original size, compressed size, compression ratio, average code length, and Shannon entropy.

Hamming Code Calculator | Error Detection & Single-Bit Correction

Encode binary data words with Hamming error-correcting codes. Supports Hamming(7,4) and Hamming(15,11). Shows parity bit placement, codeword construction, and syndrome decoding. Simulate a single-bit error by flipping any bit position and watch the calculator locate and correct the error automatically.

RSA Calculator | Key Generation, Encryption & Decryption Step-by-Step

Explore RSA public-key cryptography step by step. Enter two prime numbers p and q; the calculator derives n, φ(n), public exponent e, and private key d using the extended Euclidean algorithm. Encrypts and decrypts numeric messages with full modular exponentiation working shown at each step.

Knapsack Calculator | 0-1 Knapsack with DP Table & Fractional Comparison

Solve the 0-1 knapsack optimization problem using dynamic programming. Enter items with weights and values and a capacity; the calculator builds the complete DP table, traces back the optimal item selection, reports total value and weight, and compares the result with the fractional knapsack greedy solution.

CRC Calculator | CRC-8, CRC-16 & CRC-32 Checksum with XOR Division

Compute CRC-8, CRC-16-IBM, and CRC-32 checksums for binary strings or ASCII text. Shows the full XOR polynomial long-division process step by step, the generator polynomial used, and the resulting remainder. Verifies data integrity by appending the CRC and confirming the syndrome is zero.

Z-Transform Calculator | Transform Pairs, Properties & Inverse Z-Transform

Look up Z-transform pairs from a comprehensive table covering unit impulse, unit step, ramp, exponential, sine, cosine, and more. Apply linearity, time-shift, convolution, and differentiation properties. Compute the inverse Z-transform for causal rational polynomial fractions.

Voltage Divider Calculator

Calculate output voltage from a resistor voltage divider circuit using Vout = Vin × R2/(R1+R2).

Gear Ratio Calculator | RPM, Torque & Trains

Calculate gear ratio, output RPM, torque multiplier, and speed change for simple gear pairs and multi-stage gear trains. Visual SVG diagram included.

Beam Deflection Calculator

Calculate maximum deflection and slope for cantilever, simply supported, and fixed-fixed beams with section presets, material library, and serviceability code checks.

Pipe Flow Calculator | Darcy-Weisbach

Calculate fluid flow rate, velocity, and pressure drop in pipes using the Darcy-Weisbach equation.

Power Factor Calculator | AC Circuit

Calculate power factor, real power, reactive power, and apparent power for AC circuits.

Resistor Series & Parallel Calculator

Calculate equivalent resistance for resistors in series, parallel, or mixed configurations. Add or remove resistors dynamically and see the result instantly.

Concrete & Cement Calculator

Calculate concrete volume for slabs, footings, walls, columns, and circular pads. Shows bags needed (25 kg, 40 kg, 60 lb, 80 lb), cubic yards, and optional cost estimate.

Wire Gauge Calculator | AWG, Current & Resistance

Look up AWG wire gauge specs: current-carrying capacity (ampacity), resistance per foot, voltage drop, and cross-sectional area. Calculate wire size from current load and find safe circuit wire length.

Battery Life Calculator | Runtime & Charge Cycles

Estimate battery runtime from capacity (mAh/Wh) and current draw. Calculate charge cycles to 80% capacity, find the right battery size for your device, and compare battery packs.

Electricity Cost Calculator | Home Energy & Appliance Usage

Calculate the electricity cost of any appliance or entire home. Add multiple devices with wattage and daily hours, set your kWh rate, and get daily, monthly, and annual costs with CO₂ emissions and a ranked consumption breakdown.

Solar Panel Calculator | ROI, Payback & 25-Year Savings

Estimate solar panel energy production, annual savings, payback period, and 25-year net savings. Accounts for system size, local sun hours, electricity rate, installation cost, federal tax credit, and annual electricity price escalation.

Voltage Drop Calculator | NEC Wire Sizing & Circuit Compliance

Calculate voltage drop percentage for single-phase and three-phase AC circuits. Checks compliance with NEC 3% branch-circuit and 5% total-circuit limits, recommends the minimum wire gauge (AWG) to meet code, and supports both copper and aluminum conductors.

Fence Calculator | Posts, Panels, Concrete & Material Estimator

Calculate the exact number of fence posts, panels or boards, concrete bags, and total materials for any fencing project. Supports wood privacy, picket, split-rail, chain-link, and vinyl styles with custom gate placement and per-unit cost estimation.

Tile Calculator | How Many Tiles Do I Need?

Calculate the exact number of tiles needed for any floor, wall, or backsplash project. Accounts for waste percentage, grout width, tile orientation, and cut tiles at borders. Supports square, rectangular, and custom tile sizes with cost estimation per box or sheet.

Roof Calculator | Shingles, Squares & Roofing Materials

Calculate roofing squares, shingles, bundles, felt underlayment, ridge cap, and starter strips for any roof shape. Enter footprint dimensions and pitch to get complete material quantities with a configurable waste factor for hips, valleys, and cuts.

Deck Calculator | Boards, Joists, Posts & Material Estimator

Calculate deck boards, joists, posts, concrete footings, rim boards, and hardware for any wood or composite deck. Enter dimensions, board width, and joist spacing — with diagonal board options and a complete material summary with optional cost estimate.

Mulch Calculator | Cubic Yards, Bags & Landscaping Coverage

Calculate the exact cubic yards or number of bags of mulch, topsoil, gravel, or compost needed for any garden bed, lawn area, or landscaping project. Supports multiple shapes — rectangular, circular, and triangular — with bulk vs bagged cost comparison.

Carbon Footprint Calculator | Personal CO₂ Emissions Estimator

Estimate your annual personal carbon footprint across four major categories: home energy use, transportation, diet and food, and consumer spending. Shows total CO₂ equivalent in metric tons, comparison to US and global averages, biggest contributor breakdown, and practical reduction actions.

RLC Circuit Calculator | Resonance, Impedance & Q Factor

Analyze series and parallel RLC circuits. Computes resonant frequency, impedance at any input frequency, damping ratio, Q factor, bandwidth, and phase angle. Classifies the circuit as overdamped, critically damped, or underdamped and shows the time-domain step response type.

Stress-Strain Calculator | Young's Modulus, Poisson's Ratio & Deformation

Calculate normal stress, axial strain, lateral strain, shear stress, shear strain, and deformation for structural members under axial or shear loading. Includes Young's modulus, shear modulus, and bulk modulus with material presets for steel, aluminum, concrete, copper, and rubber. Computes safety factor against yield.

LMTD Calculator | Log Mean Temperature Difference & Heat Exchanger Design

Calculate the log mean temperature difference (LMTD) for counter-flow, parallel-flow, and cross-flow heat exchangers. Computes the LMTD correction factor F, overall heat transfer coefficient U, heat transfer area A, NTU-effectiveness, and heat duty Q = U·A·LMTD.

Signal-to-Noise Ratio Calculator | SNR, PSNR & Noise Figure in dB

Calculate signal-to-noise ratio (SNR), peak signal-to-noise ratio (PSNR), noise figure (NF), noise factor, and dynamic range for audio, electronics, and imaging applications. Converts between linear power ratios and decibels, and computes thermal noise floor.

Pool Calculator | Volume, Chlorine, pH & Chemical Dosing

Calculate swimming pool water volume in gallons for any pool shape — rectangular, oval, round, kidney, and L-shaped. Uses volume to calculate correct chlorine, shock, alkalinity adjustment, stabilizer, and pH balancing chemical doses with turnover rate and pump run time.

Customer Lifetime Value Calculator | LTV, CLV & CAC Payback

Calculate customer lifetime value using three models: historic average order value, subscription churn-based LTV, and discounted predictive CLV. Returns LTV:CAC ratio, payback period, and cohort-level revenue projection to guide acquisition spend decisions.

A/B Test Calculator | Statistical Significance, Sample Size & Bayesian Analysis

Run A/B tests with both frequentist (z-test, chi-square, p-value) and Bayesian (Beta distribution) analyses. Calculate required sample size, minimum detectable effect, test duration, and the probability that variant B truly beats the control.

Marketing Attribution Calculator | 6 Models, Channel Revenue Split & Touchpath

Compare six attribution models — first-touch, last-touch, linear, time-decay, U-shaped, and W-shaped — across any sequence of marketing touchpoints. Enter up to 10 channels with timestamps and see how each model distributes revenue credit differently.

PPC ROAS Calculator | Break-Even ROAS, Target CPA & Budget Optimizer

Calculate break-even ROAS, target CPA, and project budget performance for Google Ads, Meta, or any PPC channel. Includes impression share adjustment, quality score CPC discount and premium table, and ACOS/TACOS for Amazon advertising.

Email Revenue Calculator | Revenue Per Subscriber, List Value & Campaign ROI

Calculate your email list revenue value, revenue per subscriber (RPS), and 12-month campaign ROI. Model list decay based on monthly unsubscribe rates, deliverability tier impact on open rates, and optimal send frequency for maximum revenue.

Marketing Funnel Calculator | Conversion Rates, CPL by Stage & Revenue Projection

Map your complete marketing funnel from website visitors through leads, MQLs, SQLs, opportunities, and closed-won revenue. Calculate cost per lead at each stage, identify the highest-impact conversion leaks, and model the revenue impact of improving any stage.

SEO ROI Calculator | Organic Traffic Value, Keyword Opportunity & Break-Even

Estimate the true ROI of your SEO investment. Calculate organic traffic value using position-based CTR curves and CPC equivalents, size keyword opportunities by search volume, and determine the break-even timeline for content and link-building spend.

Influencer Marketing ROI Calculator | EMV, CPE & Audience Quality Score

Calculate influencer marketing ROI using earned media value (EMV), cost per engagement vs. paid social benchmarks, engagement rate quality scoring, fake follower adjustment, and CPM equivalence across Instagram, TikTok, and YouTube.

Viral Coefficient Calculator | K-Factor, Growth Projection & Referral Program ROI

Calculate your product viral coefficient (K-factor = invites per user × conversion rate), model exponential growth curves over multiple viral cycles, and estimate the ROI of a referral program against paid acquisition benchmarks.

SaaS Churn & Revenue Retention Calculator | MRR Churn, NRR, GRR & Expansion

Analyze SaaS churn comprehensively: separate logo churn from MRR churn, calculate Net Revenue Retention (NRR) and Gross Revenue Retention (GRR), model expansion MRR, and project revenue at risk. Includes monthly cohort retention waterfall and benchmark comparison.

CAC & Payback Period Calculator | Customer Acquisition Cost by Channel

Calculate customer acquisition cost by marketing channel, blended CAC, LTV:CAC ratio, and payback period in months. Compares results against SaaS, e-commerce, and marketplace industry benchmarks to evaluate marketing efficiency at a glance.

Social Media Ads ROI Calculator | CPM, CPC, CPL, CPA & ROAS by Platform

Model paid social campaign performance across Facebook, Instagram, TikTok, and LinkedIn. Convert between CPM, CPC, CPL, CPA, and ROAS using real platform benchmarks. Includes audience funnel analysis, frequency impact on CTR, and a budget scenario planner.

Content Marketing ROI Calculator | Production Cost, Traffic Value & Decay Curve

Calculate the full ROI of content marketing: production cost (writer, editor, designer hours × rate), organic traffic value using CTR curve and CPC equivalent, content decay over 36 months, and cumulative break-even month. Compare content types and see 3-year return.

Marketing Budget Mix Calculator | Channel ROI, Marginal Returns & Pareto Analysis

Analyze marketing budget allocation across up to 8 channels. Calculate ROI and marginal ROI per channel, identify Pareto top performers, compute blended ROAS, and model the revenue impact of shifting budget between underperforming and high-return channels.

Lead Scoring Calculator | Weighted MQL Model, Pipeline Value & Score Tiers

Build a complete weighted lead scoring model with firmographic and behavioral attributes, set the optimal MQL threshold, and calculate expected pipeline value by score tier. See conversion rates at each score band and model the revenue impact of threshold changes.

Ad Reach & Frequency Calculator | GRP, Effective Reach & Optimal Frequency Cap

Calculate advertising reach percentage, frequency distribution (1+, 2+, 3+ exposures), gross rating points (GRP/TRP), and effective reach for any media plan. Apply the Ostrow model to find the optimal frequency cap and visualize diminishing returns on reach.

NPS Revenue Impact Calculator | Promoter Value, Word-of-Mouth & ROI

Calculate your Net Promoter Score from promoter, passive, and detractor counts, then quantify the financial impact. Computes promoter vs detractor lifetime value delta, word-of-mouth amplification multiplier, and the revenue ROI of improving NPS by 10 or 20 points.

Programmatic Advertising Calculator | CPM, eCPM, Viewability & Delivery Pace

Convert between CPM, CPC, CPL, and CPA for any digital campaign. Model viewability-adjusted eCPM with configurable in-view rates, apply brand safety and targeting surcharge premiums, and calculate impression delivery pace against campaign flight dates.

Cohort LTV Calculator | Retention Curves, Revenue Waterfall & Power-Law Fit

Analyze customer cohort retention and lifetime value with up to 12 monthly cohorts. Input cohort sizes and period-by-period retention, fit power-law decay curves, and visualize a cumulative revenue waterfall. Compare LTV at 1, 3, 6, and 12 months across cohorts.

CRO Revenue Calculator | Conversion Rate Uplift, A/B Test ROI & Traffic Value

Calculate the annual revenue impact of improving your conversion rate. Model A/B test lift-to-revenue translation, compute the paid traffic equivalent of any conversion gain, and determine the break-even period for CRO tool and agency investment.

AdSense Earnings Calculator | RPM by Niche, Country & Device Mix

Estimate Google AdSense revenue with precision. Select your content niche, primary traffic country, device mix, and ad unit configuration to get pessimistic, realistic, and optimistic monthly and annual earnings ranges with seasonal adjustments and optimization insights.