Decode 4-, 5- and 6-band resistors, or find the colour bands for any resistance value.
Digit, digit, multiplier, tolerance. Brown – Black – Red – Gold = 10 × 100 = 1 kΩ ±5%. Yellow – Violet – Orange – Gold is 47 kΩ ±5%.
Resistors are marked with coloured bands that encode their value, because the parts are too small to print numbers on. This calculator reads 4-, 5- and 6-band resistors from the colours you select and gives the resistance, the tolerance and the minimum and maximum values. A second tool works backwards: enter a resistance and it tells you which colours to look for.
It is a handy bench reference for electronics students and hobbyists. Combine it with the Ohm's Law Calculator to calculate current and power in a circuit.
Every band has a defined meaning, read from the end with bands grouped closest together.
| Colour bands | Resistance |
|---|---|
| Brown – Black – Red – Gold | 1 kΩ ±5% |
| Yellow – Violet – Orange – Gold | 47 kΩ ±5% |
| Red – Red – Brown – Gold | 220 Ω ±5% |
| Brown – Black – Black – Red – Brown (5-band) | 10 kΩ ±1% |
| Brown – Black – Black – Red – Brown – Red (6-band) | 10 kΩ ±1% · 50 ppm/K |
| Colour | Digit | Multiplier | Tolerance | Temp. coeff. (ppm/K) |
|---|---|---|---|---|
| Black | 0 | ×1 | — | — |
| Brown | 1 | ×10 | ±1% | 100 |
| Red | 2 | ×100 | ±2% | 50 |
| Orange | 3 | ×1k | — | 15 |
| Yellow | 4 | ×10k | — | 25 |
| Green | 5 | ×100k | ±0.5% | — |
| Blue | 6 | ×1M | ±0.25% | 10 |
| Violet | 7 | ×10M | ±0.1% | 5 |
| Grey | 8 | ×100M | ±0.05% | — |
| White | 9 | ×1G | — | — |
| Gold | — | ×0.1 | ±5% | — |
| Silver | — | ×0.01 | ±10% | — |
Read the bands from the end closest together: the first digits give the number, the next band is the multiplier, and the last is the tolerance.
4-band resistors have two digits; 5-band have three digits for finer precision; 6-band add a temperature coefficient.
As a tolerance, gold means ±5%. As a multiplier, gold means ×0.1.
Brown – Black – Red – Gold for ±5% (1, 0, ×100).
Red – Red – Brown – Gold (2, 2, ×10).
Yellow – Violet – Red – Gold (4, 7, ×100).
How far the real resistance can differ from the marked value. A 1 kΩ ±5% resistor can be anywhere from 950 to 1,050 Ω.
How much the resistance changes with temperature, in parts per million per kelvin (ppm/K). Lower is more stable.
Use the second calculator: enter the resistance and tolerance and it lists the colour bands.
No. Everything runs in your browser.
