Resistor Color Code Calculator
Read a resistor's value from its colour bands.
Reading the bands
Resistors are marked with coloured bands. The first bands give digits, the next gives the multiplier (a power of ten) and the last gives the tolerance, which is how far the real value may differ from the marked one.
Example
On the first tab (4 bands) with the starting values shown (Band 1 Yellow; Band 2 Violet; Band 3 Red (×100); Band 4 Gold (±5%)), Resistance comes out as 4.7 kΩ ±5%. Other results include lowest value: 4.465 kΩ; highest value: 4.935 kΩ; in ohms: 4,700 Ω.
Hold the resistor with the tolerance band (often gold or silver) on the right and read from the left. If two ends look alike, the tolerance band is usually spaced a little further from the others. A multimeter is the sure way to check.
Frequently asked questions
What does tolerance mean?
The allowed difference from the marked value. A 5% 100 Ω resistor can measure between 95 and 105 Ω.
How do I know which end to start from?
Start from the end opposite the gold or silver tolerance band.
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