Resistor Color Code Calculator
Decode 4-band and 5-band resistor color codes to find resistance and tolerance.
What Is the Resistor Color Code Calculator?
The Resistor Color Code Calculator decodes the colored band markings on resistors to give the resistance value and tolerance. It supports 3-band, 4-band, 5-band, and 6-band resistors. You can also enter a resistance value to find the corresponding color code.
Formula
How to Use
Select the number of bands (4 or 5 is most common). Choose the color of each band from the dropdowns — from left to right. The calculator instantly displays the resistance value in ohms, the tolerance percentage, and for 6-band resistors, the temperature coefficient.
Example Calculation
4-band resistor: Yellow (4), Violet (7), Red (×100), Gold (±5%): R = (4×10+7) × 100 ± 5% = 4700 Ω ± 5% = 4.7 kΩ ±5%. 5-band: Brown(1), Black(0), Black(0), Red(×100), Brown(±1%): R = 100×100 ±1% = 10,000 Ω = 10 kΩ ±1%.
Understanding Resistor Color Code
The resistor color code is a standardized system (IEC 60062) used since the 1920s to mark small resistors where printed numbers would be too small to read. The colored bands are visible from any angle, making component identification quick during circuit assembly and repair.
Reading color codes is a fundamental skill for electronics hobbyists, engineers, and technicians. The most common is the 4-band code: two significant digits, one multiplier, one tolerance band. The 5-band code adds a third significant digit for higher precision (1% and 2% resistors are almost always 5-band).
Beyond resistance value, 6-band resistors include a temperature coefficient band (ppm/°C), important for precision circuits that must maintain accuracy across temperature ranges. This calculator handles all band configurations and also performs the reverse: given a target resistance, it finds the nearest standard value and displays its color bands.
Frequently Asked Questions
What is the resistor color code?
The resistor color code is a system of colored bands printed on resistors to indicate their resistance value and tolerance. Each color represents a digit (0-9), a multiplier power of 10, or a tolerance percentage.
What do the colors represent?
Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9. For multipliers: Black=×1, Brown=×10, Red=×100...Gold=×0.1, Silver=×0.01.
What do tolerance bands mean?
Gold=±5%, Silver=±10%, Brown=±1%, Red=±2%, Green=±0.5%, Blue=±0.25%, Violet=±0.1%. A 1kΩ ±5% resistor measures between 950Ω and 1050Ω.
How do I read a 5-band resistor?
Bands 1, 2, 3 are the first three significant digits. Band 4 is the multiplier. Band 5 is tolerance. Start from the end with more bands, or the end nearest the gold/silver tolerance band.
Is this calculator free?
Yes, completely free with no registration required.
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