Resistor Color Code
Decode 4-band, 5-band, and 6-band resistor color codes to find resistance in ohms, tolerance, and temperature coefficient. Also converts a resistance value to color bands.
How to use the resistor color code
Pick the band count printed on your resistor (4 is most common; 5 is precision; 6 adds temperature coefficient). Then choose each band's colour. The decoded resistance, tolerance, and (for 6-band) temperature coefficient appear instantly.
Formula & explanation
4-band: value = (digit1 × 10 + digit2) × 10^multiplier. 5- and 6-band: value = (digit1 × 100 + digit2 × 10 + digit3) × 10^multiplier. Multiplier can be 10⁻² (silver) to 10⁹ (white). Tolerance band gives the ± percent. The 6-band temperature coefficient is in parts-per-million per °C.
Examples
Red-Red-Red-Gold (4-band) = 2,200 Ω ±5% = 2.2 kΩ. Brown-Black-Black-Red-Brown (5-band) = 10,000 Ω ±1% = 10 kΩ. Yellow-Violet-Black-Orange-Brown-Red (6-band) = 47 kΩ ±1%, 50 ppm/°C.
Frequently asked questions
- Which side do I read from?
- Tolerance band is usually slightly wider and offset to one end. Read from the opposite end. If both ends look symmetric, gold/silver is always the tolerance band.
- What's the difference between 4 and 5 bands?
- 4-band gives 2 significant digits; 5-band gives 3, useful for tighter-tolerance resistors (1% or better).
- Why doesn't black appear as a tolerance?
- Black has no defined tolerance value. Tolerance is one of brown/red/green/blue/violet/gray/gold/silver per IEC 60062.
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