Resistor Color Code Calculator

Decoding a 4-band resistor comes down to reading four stripes of color and translating them into ohms, or running that process in reverse to find which bands produce a target value. For anyone building, repairing, or studying circuits in 2026, getting this right the first time saves real money: a typical hobbyist project runs roughly $75 to $250 in parts, and a single misread band can mean ordering the wrong component or chasing a fault that was never there.

The color scheme follows the Electronic Industries Alliance (EIA) standard used worldwide. On a 4-band part, the first two bands give the significant digits, the third band sets the multiplier as a power of ten, and the fourth band states the tolerance. Every color maps to one specific digit, multiplier, or tolerance percentage, so the conversion between the painted stripes and a numerical resistance is fully systematic once you know the order.

Reading direction is where most errors creep in. The tolerance band usually sits a little wider or with a noticeable gap, which tells you which end to start from; flip the resistor and you can swap the first significant digit with the last and land on a wildly wrong value. Brown, red, and orange are the colors most often confused under dim or yellow light, so confirm those shades against a known-good reference before you trust the reading.