The coloured bands on a resistor tell you its value, and a resistor color code chart is all you need to decode them. This guide gives the full chart and shows how to read both 4-band and 5-band resistors.

The resistor color code chart

Each colour stands for a digit, a multiplier, and, for some, a tolerance. This is the standard resistor colour code chart:

How to read a 4-band resistor

On a four-band resistor the first two bands are digits, the third is a power-of-ten multiplier, and the fourth is tolerance. Read from the end where the bands are grouped, with the tolerance band (often gold or silver) on the right. For example, brown-black-red-gold is 1, 0, ×100, so 10 × 100 = 1000 Ω, or 1 kΩ at ±5%. The resistor color code calculator decodes any combination instantly.

How to read a 5-band resistor

A five-band resistor adds a third digit band for tighter precision. The first three bands are digits, the fourth is the multiplier, and the fifth is tolerance. That extra digit lets a manufacturer specify a value like 4.99 kΩ instead of rounding, which is why precision parts use five bands.

Reading tips

• Find the tolerance band first. It sits slightly apart and is usually gold or silver; keep it on the right.
• Watch faded colours. Red and orange blur under poor light, so confirm an ambiguous part with a meter.
• Mind gold and silver. As a multiplier they mean ×0.1 and ×0.01; as a tolerance they mean ±5% and ±10%.

Using the value

Once you know the resistance, the rest of the circuit follows. The Ohm’s law calculator relates it to voltage and current.

For driving an LED, the LED resistor calculator sizes the series resistor you need. Keep this resistor color code chart handy.

For the rest of the circuit math, CalculateGuide has free electronics tools for dividers, capacitors, and power.