Resistor Color Decoder

What is a resistor color code?

Resistors use colored bands to indicate their resistance value, tolerance, and sometimes temperature coefficient. The system was standardized because resistors are too small for printed numbers to be reliably readable. Each color represents a digit (0–9) and the bands are read in sequence: significant digits, multiplier, and tolerance.

Four-band resistors are the most common: two digit bands, one multiplier, one tolerance. Five-band resistors add a third digit for greater precision (used in 1% and 0.1% tolerance resistors). Six-band resistors include a temperature coefficient band. The color sequence is: black=0, brown=1, red=2, orange=3, yellow=4, green=5, blue=6, violet=7, gray=8, white=9.

How to read resistor bands

Start from the band closest to one end of the resistor. Read the first two (or three) bands as digits. The next band is the multiplier — it tells you how many zeros to add. The last band is the tolerance. Example: brown-black-red-gold = 1, 0, x100 = 1,000 ohms (1K) with 5% tolerance.

How to use this tool

Select the color for each band using the visual color picker. Choose between 4-band, 5-band, or 6-band mode. The decoded resistance value appears instantly with the tolerance range. You can also enter a resistance value to see the expected color code.

Tolerance bands explained

• Gold = 5% — The most common tolerance for general-purpose resistors.
• Silver = 10% — Lower precision, used in non-critical applications.
• Brown = 1% — Precision resistors for accurate circuits.
• No band = 20% — Older or very cheap resistors.

Frequently asked questions

Which end do I start reading from?

The tolerance band (gold or silver) is always at the end. Start reading from the opposite end. If there is no gold or silver band, the first band is usually closer to one end of the resistor body. With 5-band resistors, the tolerance band has a wider gap before it.

Why not just print the value on the resistor?

Some modern resistors do print the value, especially larger power resistors. But standard 1/4-watt resistors are very small (about 6mm long), and printed text would be nearly impossible to read, especially after soldering. Color bands are visible from any angle and do not wear off. SMD resistors use printed numeric codes instead.