Resistor Color Code Calculator
Decode a resistor's colour bands into its resistance, tolerance and temperature coefficient, or encode a resistance value back into 4-, 5- or 6-band colours. Shows the value range and a colour-band diagram of the resistor.
Input
Read bands into a value, or find the bands for a value.
The band in decode mode; the desired tolerance in encode mode.
Output
| Property | Value |
|---|---|
| No data yet | |
The resistor diagram will appear here.
Guides
The Resistor Color Code Calculator reads the coloured bands printed on a through-hole resistor and tells you its resistance, tolerance and — for precision parts — its temperature coefficient. It works both ways: pick the band colours to get the value, or type a value to find the bands you need.
How to read a resistor
Axial resistors encode their value with 4, 5 or 6 painted bands, read from the end where the bands are grouped closest together:
- 4-band — two significant-digit bands, a multiplier, and a tolerance band.
- 5-band — three digit bands, a multiplier, and a tolerance band. Used for precision (1% and tighter) parts.
- 6-band — the 5-band layout plus a temperature-coefficient (TCR) band that states how much the resistance drifts per degree, in ppm/K.
Each digit colour maps to a number (Black 0, Brown 1, Red 2, Orange 3, Yellow 4, Green 5, Blue 6, Violet 7, Grey 8, White 9). The multiplier band is a power of ten, and gold/silver multipliers (×0.1, ×0.01) give sub-ohm values.
Using the calculator
Choose the Direction:
- Colours → Value — set the number of bands, then pick each band's colour. The calculator shows the nominal resistance, the ± tolerance, the resulting min–max value range, and a diagram of the resistor.
- Value → Colours — type a resistance and the calculator finds the closest
standard band combination. It accepts plain values (
470,4700), suffixed values (4.7k,2.2M,220R), and European shorthand where the multiplier letter is the decimal point (4k7= 4.7 kΩ,2M2= 2.2 MΩ,R47= 0.47 Ω).
The tolerance and temperature-coefficient selectors are shared by both directions — in decode mode they read the physical band, and in encode mode you choose them for the resistor you want, since they can't be inferred from a bare resistance number.
Tolerance and value range
A resistor's real value can sit anywhere inside its tolerance band. A 470 Ω ±5% resistor is guaranteed only to fall between 446.5 Ω and 493.5 Ω; a 1% part of the same nominal value narrows that to 465.3–474.7 Ω. The value-range row makes this explicit so you can judge whether a tighter-tolerance part is worth it.
Which end do I start from?
Read from the end where the bands are bunched together, or where a lone gold/silver tolerance band sits at the opposite end. If you read a resistor backwards you'll usually get an obviously wrong value (a huge multiplier), which is a good sign to flip it around.
Everything runs in your browser
The calculation is pure arithmetic and happens entirely on your device — no values are sent to a server.