Find the value of a 4-band or 5-band resistor from its colour bands, with tolerance and the min–max range. Enter your values; the result updates as you type, with the method shown below.
About this calculator
Resistors are marked with coloured bands. This decoder turns the bands into a resistance value with its tolerance range.
Choose the colours of the digit bands, the multiplier and the tolerance band.
When to use it
- Electronics hobby projects.
- Sorting a box of resistors.
- School electronics.
- Repairing a circuit board.
How to read the result
Value = digits × 10^multiplier. Brown, black, red = 10 × 10² = 1 kΩ; a gold band means ±5%.
Read the bands starting from the end opposite the tolerance band (often gold or silver).
Mistakes to avoid
- Reading the bands from the wrong end.
- Confusing red and orange, or brown and violet, under poor light.
- Forgetting the tolerance range.
Formula
R = digits × 10^multiplier ± tolerance
Worked example
Brown, black, red, gold: 1 kΩ ±5%.
Frequently asked questions
Which side do I read from?
Start from the band farthest from the gold or silver tolerance band.
4 or 5 bands?
5-band resistors have three digits and are more precise.
Which end do I start from?
The end opposite the gold or silver band.
What does gold mean?
±5% tolerance, or ×0.1 as a multiplier.
Can I check with a multimeter?
Yes, out of the circuit.
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Results are estimates for information only. Check important figures with a professional.