Resistor Colour Code
Decode a resistor's colour bands into a resistance and tolerance, with a drawn resistor that updates as you pick each band, plus the full colour table.
How to use it
- Choose four bands for a standard resistor or five for a precision one.
- Set each band's colour — the drawing and the value update immediately.
- The minimum and maximum tiles show the real range the resistor is guaranteed to fall within.
Examples
| Brown, black, red, gold | 1 kΩ ± 5% |
| Yellow, violet, orange, gold | 47 kΩ ± 5% |
Resistors are too small to print a value on, so manufacturers use coloured bands instead — a code that has stayed essentially unchanged since the 1920s. A 4-band resistor gives two significant digits, a multiplier and a tolerance; a 5-band gives three significant digits for tighter, more precise parts.
This tool decodes the bands as you set them, drawing the resistor and showing the resulting value, the tolerance range, and the colour-to-number mapping underneath.
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 | ×100,000,000 | ±0.05% |
| White | 9 | ×1,000,000,000 | — |
| Gold | — | ×0.1 | ±5% |
| Silver | — | ×0.01 | ±10% |
4-band vs 5-band vs 6-band
A 4-band resistor reads as two digits, a multiplier and a tolerance — the most common type in general electronics. A 5-band adds a third significant digit, used for precision resistors down to ±1% or better. A 6-band adds a temperature coefficient band after the tolerance, specifying how much the value drifts per degree Celsius, which matters in precision analog circuits but rarely elsewhere.
Reading the bands the right way round
Start from the end where the bands are grouped closer together — that is the first significant digit. The tolerance band, almost always gold or silver and sometimes set slightly apart with a wider gap, marks the other end. If a resistor is symmetrical enough to be ambiguous, the wider gap before the tolerance band is the tell.
What tolerance actually guarantees
A 1 kΩ resistor with a gold tolerance band is guaranteed to measure between 950 Ω and 1,050 Ω, not exactly 1,000 Ω. A multimeter reading 987 Ω on that part is completely in spec. Tighter tolerances cost more and are only worth specifying where the circuit actually needs the precision — a simple LED current-limiting resistor rarely does.
Questions people ask
Which end do I read from?
Start at the end where the bands are closest together. The tolerance band — usually gold or silver — sits slightly apart at the other end.
What if there is no tolerance band?
Three bands means ± 20% by default. That is rare in modern parts; almost everything today is at least ± 5%.
Why does my meter read slightly differently?
Because the tolerance band is a guarantee, not a promise of exactness. A 1 kΩ ± 5% resistor is in spec anywhere from 950 Ω to 1050 Ω.
Does this page work offline?
Yes, after the first visit. The service worker caches it, so the reference stays available with no connection.
Last updated 22 August 2026