Resistor Calculator
Color Code to Resistance Value
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Select the color bands on your resistor to decode its resistance value.
Reading Resistor Color Codes
Resistors are too small to print resistance values on directly, so manufacturers use a standardized color-band code instead. Each color represents a digit, and the position of the band determines whether it's a significant digit, a multiplier, or a tolerance rating.
4-Band vs. 5-Band
4-band resistors use two significant digits, a multiplier, and a tolerance band. 5-band resistors add a third significant digit for higher precision, common in 1% tolerance parts.
Reading Direction
Read bands from the side with the least space after the last band — the tolerance band (often gold or silver) is usually separated slightly from the rest and marks the end of the code.
The Color-to-Digit Key
Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Gray=8, White=9. A popular mnemonic — "Bad Boys Race Our Young Girls, But Violet Generally Wins" — helps recall the order.
Tolerance Bands
Gold = ±5%, Silver = ±10%, Brown = ±1%, Red = ±2% — this tells you the real-world manufacturing variance to expect.
Key Takeaways
- Gold & Silver Multipliers: When used as the multiplier band, gold means ×0.1 and silver means ×0.01 — used for resistances under 10 Ω.
- Verify With a Meter: Color codes can fade or be misread — a multimeter reading is always the most reliable confirmation.
- Expected Range: The tolerance percentage defines the acceptable measured range around the nominal value — a resistor rarely measures the exact printed value.