Resistor Calculator guide
Resistor Calculator: Read the Colour Code
Use our resistor calculator to read the resistance, tolerance and temperature coefficient from a 4, 5 or 6-band resistor's colour code.
By the AllCalculator editorial teamUpdated 16 October 20261 min read
Resistors are too small to print numbers on, so their value is shown with coloured bands. Our Resistor Calculator decodes them.
How to use the calculator (Resistor Calculator)
- Choose the number of bands: 4, 5 or 6.
- Choose the colour of each band, starting from the end furthest from the gold or silver band.
You'll see the resistance, tolerance and the range the real value can be in.
The colour code
| Colour | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | — |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1,000 | — |
| Yellow | 4 | ×10,000 | — |
| Green | 5 | ×100,000 | ±0.5% |
| Blue | 6 | ×1,000,000 | ±0.25% |
| Violet | 7 | ×10,000,000 | ±0.1% |
| Grey | 8 | — | ±0.05% |
| White | 9 | — | — |
| Gold | — | ×0.1 | ±5% |
| Silver | — | ×0.01 | ±10% |
How to read the bands
- 4 bands: two digits, a multiplier and a tolerance.
- 5 bands: three digits, a multiplier and a tolerance (for precision resistors).
- 6 bands: as 5 bands, plus a temperature coefficient.
A worked example
With the calculator's default settings, yellow, violet, red, gold means 4, 7, × 100, ±5%: 4,700Ω (4.7kΩ) ±5%, so anywhere from 4.465kΩ to 4.935kΩ.
Frequently asked questions
Which end do I start from?
The tolerance band (often gold or silver) is usually a little apart from the others. Start from the other end.
How can I check the value?
Use a multimeter on the resistance setting, with the resistor out of the circuit.
To work out current and power, use our Ohm's Law Calculator.
Sources and further reading
Links open official and independent websites in a new tab.
This guide is general information to help you understand your options. It isn't financial, tax, legal or building advice and doesn't take your personal circumstances into account. Figures were checked when the guide was last updated and can change, so confirm anything important with GOV.UK, HMRC, a regulated adviser or a qualified tradesperson.