Resistor Colour Code Decoder

How to Read Resistor Colour Codes

Resistors use a series of coloured bands to indicate their resistance value, tolerance and (on precision types) temperature coefficient. The colour code system was introduced by the Radio Manufacturers Association in the 1920s and remains the universal standard today.

Each colour corresponds to a digit (0–9), a multiplier power of ten, and a tolerance percentage. Reading the bands from left to right gives the resistance value.

4-Band Resistors

The most common type. The first two bands are significant digits, the third is the multiplier (10ⁿ), and the fourth is the tolerance. For example, yellow-violet-brown-gold = 4, 7, ×10, ±5% = 470 Ω ±5%.

5-Band Resistors

Used for precision resistors (1% or better). Three significant digits, one multiplier, one tolerance band. They offer finer granularity — e.g. yellow-violet-black-brown-brown = 4, 7, 0, ×10, ±1% = 4700 Ω ±1%.

6-Band Resistors

Military and high-precision resistors add a sixth band for temperature coefficient (ppm/°C), indicating how much the resistance drifts with temperature. A brown 6th band means 100 ppm/°C — for every 1°C rise, resistance changes by 100 parts per million.

Colour Code Quick Reference