How the color code works
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). A 4-band resistor reads digit-digit-multiplier-tolerance; a 5-band adds a third digit for precision values; a 6-band adds the temperature coefficient:
Worked example
Yellow-violet-red-gold:
- Digits: 4, 7 → 47
- Multiplier red = ×100 → 4.7 kΩ
- Gold → ±5%, so 4,465–4,935 Ω actual
Field notes
- Mnemonic: "BB ROY of Great Britain had a Very Good Wife" — the classic Indian classroom version for black through white.
- Gold/silver are never digits — if you're reading one first, flip the resistor.
- In instrumentation, the 250 Ω loop resistor (red-green-brown) and precision 1% 5-band values dominate — verify with a multimeter before trusting a tiny, faded band.
- Pair with the Ohm's law calculator to check power dissipation at your operating current.
Frequently asked questions
How do I read a 4-band resistor?
First two bands are digits, third is the multiplier, fourth is tolerance. Red-red-brown-gold is 22 × 10 = 220 Ω ±5%.
What is the difference between 4-band and 5-band resistors?
A 5-band resistor has three digit bands before the multiplier, giving finer values — typical of 1% precision resistors. Brown-black-black-red-brown is 100 × 100 = 10 kΩ ±1%.
Which end do I read from?
Start from the band nearest an end; the tolerance band (often gold or silver) sits slightly apart at the other end. If in doubt, a gold or silver band is never a first digit.
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