Resistor color code calculator.

How to read a resistor color code

Read the digit bands, multiply by the multiplier band, then apply the tolerance. On a 4-band resistor the first two bands are digits, the third is the multiplier and the fourth is the tolerance. A 5-band resistor has three digit bands. A 6-band resistor adds a temperature-coefficient band at the end.

Worked example (4 band). Yellow, violet, red, gold: yellow = 4, violet = 7, red = ×100, gold = ±5%. That is 47 × 100 = 4.7 kΩ, with a range of 4.465 kΩ to 4.935 kΩ.

Worked example (5 band). Brown, black, black, red, brown: 1, 0, 0, ×100, ±1%. That is 100 × 100 = 10 kΩ ±1%.

Digits: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. Multipliers: the digit colors give ×1 to ×10⁹, gold is ×0.1 and silver is ×0.01. Tolerance (IEC 60062 table): gold ±5%, silver ±10%, brown ±1%, red ±2%, green ±0.5%, blue ±0.25%, violet ±0.1%, grey ±0.01%, orange ±0.05%, yellow ±0.02%, no band ±20%. Temperature coefficient (6th band): black 250, brown 100, red 50, orange 15, yellow 25, green 20, blue 10, violet 5, grey 1 ppm/K.

Which end do I start from? Gold and silver are never digit bands, so a gold or silver band is at the tolerance end. Otherwise the tolerance band is often set slightly apart from the others. If both ends could work, measure the part with a meter. Faded or burnt bands also make color reading unreliable, and a meter reading beats any chart.

When you enter an ohm value the tool gives exact colors only. A value that needs more digits than the band count allows (for example 4.75 Ω on 4 bands) is refused rather than rounded, so pick the nearest standard value or use 5 bands.