How the color code works
Small through-hole resistors are too small to print a value, so they carry colored bands. Each color stands for a digit, a multiplier or a tolerance.
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1k | |
| Yellow | 4 | ×10k | |
| Green | 5 | ×100k | ±0.5% |
| Blue | 6 | ×1M | ±0.25% |
| Violet | 7 | ×10M | ±0.1% |
| Grey | 8 | ×100M | ±0.05% |
| White | 9 | ×1G | |
| Gold | ×0.1 | ±5% | |
| Silver | ×0.01 | ±10% |
Reading a 4-band resistor
The first two bands are digits, the third is the multiplier and the fourth is the tolerance. Example: yellow, violet, red, gold:
- digits 4 and 7 make 47;
- red multiplier ×100 gives 4,700 Ω = 4.7 kΩ;
- gold means ±5%, so the real value lies between 4,465 and 4,935 Ω.
Reading a 5-band resistor
Precision resistors use three digit bands, then the multiplier and tolerance. Example: brown, black, black, brown, brown = 100 × 10 = 1 kΩ ±1%. A sixth band, when present, gives the temperature coefficient.
Which end to start from
- The tolerance band (often gold or silver) is usually set slightly apart, at the right.
- Gold and silver never appear as the first band.
- A first band of black is very unusual.
- If in doubt, measure with a multimeter, out of circuit.
Standard values
Resistors come in E-series values: E12 (10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82) for ±10%, E24 for ±5% and E96 for ±1%. If your reading is not a standard value, you may be reading it backward.
Memory aid
The digit order follows black, brown, then the rainbow (red, orange, yellow, green, blue, violet), then grey and white. Thinking “black and brown, then the rainbow, then grey and white” is enough to recall it.