Resistor Color Codes Explained: How to Read Any Resistor

Every resistor in your lab kit is labeled in a language most students never formally learn: colored bands. Learn the code once and you'll decode components in seconds — no multimeter required for a first guess.

The code

Each color is a digit: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. Gold and silver are never digits — they're multipliers or tolerances.

4-band resistors

value = (band1 × 10 + band2) × 10^band3

Brown-black-red-gold: digits 1 and 0 make 10, red means ×10², so 10 × 100 = 1,000 Ω, and gold means ±5% tolerance. Result: 1 kΩ ± 5% — the most common resistor on earth.

5-band resistors

Same idea with three digits: brown-black-black-red-brown = 100 × 10² = 10,000 Ω (10 kΩ) ± 1%. Three-digit codes are for precision values.

Which end do you read from?

The tolerance band (gold, silver, or a thin brown) is usually on the right, slightly separated from the others. Read left to right from the other end. When bands are evenly spaced (old resistors), measure with a multimeter or try both directions — one will decode to a standard value.

Tolerance and range

Tolerance tells you the guaranteed range: a 1 kΩ ± 5% resistor measures between 950 Ω and 1,050 Ω. Tighter tolerances (1%, 0.5%) cost more and matter only in precision circuits.

Common mistakes

• Reading from the wrong end — the tolerance band is your anchor.
• Confusing red (2) and orange (3) in poor light — check the multiplier against the decoded value; standard values are your sanity check.
• Using gold/silver as digits — they're multipliers (×0.1, ×0.01) or tolerances, never digits.

Decode any resistor instantly with the Resistor Calculator — pick the band colors and get value, tolerance and range.