Resistor colour code
Pick the colours from the end of the resistor closer to the edge, or type a resistance and read the bands that encode it.
- Bands and ohms
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Band colours follow IEC 60062. Read the bands from the end closer to the edge, or type a resistance and the page builds the bands.
Resistance to bands
A 4-band code uses two significant figures. A 5-band or 6-band code uses three.
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How to use it
- Choose 4, 5 or 6 bands.
- Set each colour. The resistor picture updates with the bands.
- Read the ohms, the tolerance and, on a 6-band resistor, the temperature coefficient.
How a band becomes a number
Digit bands use black as 0 through white as 9. The multiplier band is a power of ten, with gold as ×0.1 and silver as ×0.01. A 4-band resistor uses two digit bands, then the multiplier, then tolerance. A 5-band resistor adds a third digit. The sixth band is the temperature coefficient in ppm/K. Tolerance colours are brown 1%, red 2%, green 0.5%, blue 0.25%, violet 0.1%, grey 0.05%, gold 5%, silver 10% and a missing band 20%.
The values follow IEC 60062. The sample 4-band code brown, black, red, gold is 10 × 100 = 1,000 Ω at ±5%, so the resistor sits between 950 Ω and 1,050 Ω. Turning ohms back into bands rounds to two significant figures for four bands and three for five or six. A value such as 1,234 Ω becomes the 1,200 Ω code.
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Questions
Which end do I start from?
Start at the end where the bands sit closer to the edge. The tolerance band, often gold or silver, is the last one.
What is brown, black, red, gold?
1, 0 and a multiplier of 100, with a 5% tolerance: 1,000 Ω ± 5%.
Can I go from ohms back to colours?
Yes. Open Resistance to bands and type the ohms. The page builds the nearest code and shows the value that code records.
What does the sixth band mean?
It is the temperature coefficient in parts per million per kelvin. Brown is 100 ppm/K, red is 50, orange is 15, yellow is 25, green is 20, blue is 10, violet is 5 and grey is 1.