Resistor Calculator

Convert color codes from resistors to the amount of resistance and vice versa, using this handy tool!

Resistor color code Select the color code or display the calculated resistor
Use 5 bands
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Resistance Enter the desired resistance or view the calculated value
Resistance {{resistance() | numberFormat}} Ω
Tolerance ± {{tolerance()}}%

How does it work?

Each resistor is decorated with 4 or 5 bands. The first two or three bands determine respectively the first two or three digits of the amount of resistance. Each color here represents a certain digit. The following digit then tells by which factor of 10 the obtained number should be multiplied.

For example, a brown band (1) followed by a black band (0) and a red band (2) represents the value 10 * 10 ^ 2 = 1000 Ω

The last band encodes the tolerance of the resistor. This can be considered as the "accuracy" of the resistor. Due to temperature and aging, the resistance is not always exactly as stated. For example, the resistance of a resistor with 1000 Ω and a tolerance of 10% has an actual resistance between 900 and 1100 ohms.