How to Read Resistor Color Codes
The colored bands on a resistor are a compact code for its value and tolerance. Once you know how to read them, you can identify any resistor at a glance. This guide walks through the color code, the band layouts, and how to avoid the usual mistakes.
The color-to-digit chart
Each color stands for a digit: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. The same colors act as multipliers (powers of ten) and, for gold and silver, as tolerance values — gold ±5%, silver ±10%.
Memorising the sequence is worthwhile, but our resistor calculator lets you pick each band's color and reads off the value, and works backward from a value to the band colors too.
4, 5, and 6-band layouts
On a 4-band resistor, the first two bands are significant digits, the third is the multiplier, and the fourth is tolerance. A 5-band resistor adds a third significant digit for precision parts. A 6-band resistor adds a final band for the temperature coefficient.
So brown-black-red-gold is 1, 0, ×100, ±5% — that is 1,000 Ω, or 1 kΩ, at 5% tolerance. Adding a digit for a 5-band part simply makes the value more precise.
Reading direction and standard values
The usual stumbling block is which end to start from. The tolerance band — often gold or silver, and usually set slightly apart by a wider gap — goes on the right; orient the resistor that way and read left to right.
Resistors come in standard value series (E12, E24, and finer) rather than arbitrary numbers, so a value you calculate for a circuit is rounded to the nearest standard part, or made by combining resistors in series or parallel.
Frequently asked questions
Which end of a resistor do I read first?
Start from the end opposite the tolerance band. The tolerance band (often gold or silver) sits on the right, usually with a wider gap before it; read the color bands from left to right.
What does brown-black-red-gold mean?
Brown 1, black 0, red ×100, gold ±5% — a 1,000 Ω (1 kΩ) resistor at 5% tolerance.