Science & engineering
Resistor colour code reader
Decode four- or five-band resistor values and tolerance limits.
A clear answer. Here’s how.
Reads the leading two or three digits, multiplies by the selected decimal factor, then applies the tolerance symmetrically. The first band cannot be black. Four- and five-band value/tolerance codes are supported; zero-ohm links, missing tolerance bands, six-band temperature coefficients, manufacturer exceptions and SMD markings are excluded.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Number of colour bands
- Four: two digits, multiplier, tolerance
- First digit band
- Brown
- Second digit band
- Black
- Multiplier band
- Red
- Tolerance band
- Gold ±5%
Example result
- Nominal resistance
- 1,000 Ω
- Tolerance
- 5%
- Lower resistance limit
- 950 Ω
- Upper resistance limit
- 1,050 Ω
- Bands in reading order
- brown · black · red · gold