Free Health & Fitness Calculators

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.