Electronics CalculatorsResistor colour code calculator
Choose the bands to read a resistor, or type a value to see the colours to look for.
How the code works
A resistor has bands of colour. On a 4-band resistor, the first two are digits, the third is a multiplier (a power of ten) and the fourth is the tolerance. On a 5-band resistor, three bands are digits. A sixth band gives the temperature coefficient.
| Colour | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1 k | |
| Yellow | 4 | ×10 k | |
| Green | 5 | ×100 k | ±0.5% |
| Blue | 6 | ×1 M | ±0.25% |
| Violet | 7 | ×10 M | ±0.1% |
| Grey | 8 | ×100 M | ±0.05% |
| White | 9 | ×1 G | |
| Gold | ×0.1 | ±5% | |
| Silver | ×0.01 | ±10% |
Example: yellow, violet, red, gold is 4 and 7, times 100, so 4,700 ohm (4.7 kΩ) with ±5%.
About the table
The table is the one printed in common electronics references. The standard behind it, IEC 60062, is a paid document that we did not read, so check a data sheet if a design depends on a rare band such as a temperature coefficient.
How it was tested
We read every one of the 9,600 four-band combinations (ten first digits, ten second digits, twelve multipliers and eight tolerances) and 1,500 random five-band ones with the calculator and with a separate Python table, and the values and tolerances matched. We also converted 1,200 values to bands and back.
Reading tips
- The tolerance band sits a little apart from the others. Start reading from the other end.
- A gold or silver band in the first positions is never a digit. If the code starts with gold, you are holding the resistor backwards.
- Colours fade and look alike (brown, red, orange). Measure the resistor with a multimeter when it matters.
Is the first band the thick one?
Not reliably. Use the gap before the tolerance band.
What about a single black band?
A single black band marks a zero-ohm link. This tool does not handle it.
This is an independent guide. It is not connected with any standards body or company named here. The formulas are the usual textbook ones; the colour code, E-series and AWG values are those printed in common references, because the standards IEC 60062, IEC 60063 and ASTM B258 are paid documents that we did not read. Tables and examples were calculated with Python on 14 November 2026. Check data sheets and local safety rules before you build.