Decode a 4-band resistor’s colour code into its resistance and tolerance.
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How do you read a 4-band resistor color code?
Resistance = (digit1 × 10 + digit2) × multiplier, and the fourth band gives the tolerance (gold ±5%, silver ±10%). Read the bands from the end where they are grouped closest together. For example, brown, black, red, gold reads (1, 0, ×100, ±5%) = 1,000 Ω (1 kΩ) ±5%. The tool reports the value in ohms, kΩ or MΩ.
Understanding your result
Read the bands from the end where they’re grouped closest together; the tolerance band (often gold or silver) is on the opposite end.
Formula and method
Resistance = (digit1 × 10 + digit2) × multiplier. The fourth band gives the tolerance (gold ±5%, silver ±10%).
Worked example
Brown, black, red, gold reads (1, 0, ×100, ±5%) = 1,000 Ω (1 kΩ) ±5%.
How to use this tool
- Select the colour of each of the four bands.
- Read the resistance and tolerance instantly.
About the Resistor Color Code Calculator
The Resistor Color Code Calculator decodes a standard 4-band resistor: two digit bands, a multiplier and a tolerance, giving the resistance and its range.
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Frequently asked questions
What does the gold band mean?
As the fourth band it means ±5% tolerance. As a multiplier band it means ×0.1.