Resistor Color Code Calculator – Formula & Examples

About the Resistor Color Code Calculator

Resistor colour bands encode the value as significant digits followed by a multiplier and a tolerance. Pick the colours you can see, reading from the band closest to one edge, and this calculator gives the resistance, the tolerance and the true range the part is guaranteed to fall inside.

Also known as: resistor colour code, 4 band resistor, 5 band resistor, resistor bands, read resistor value, color code resistor.

How to use this calculator

Enter number of bands, band 1, band 2, multiplier band and the other fields.
The result updates instantly as you type — press Calculate (or Enter) at any time.
Open “Step-by-step” to see how the answer was worked out.
Use Copy result or Share to save the answer or send a link with your inputs.

Formula

R = digits × 10^multiplier, ± tolerance

Worked example

Using the values pre-filled in the calculator above:

Number of bands: 4 bands
Band 1: Brown (1)
Band 2: Black (0)
Multiplier band: Red (×100)
Tolerance band: Gold (±5%)

the calculator returns:

Resistance: 1 kΩ
Ohms: 1,000
Tolerance: ±5%
Minimum: 950 Ω

Working

Digits: 10
Multiplier: ×10^2
10 × 10^2 = 1 kΩ

Frequently asked questions

Which end do I read from?

Start from the band closest to one end. The tolerance band (often gold or silver) is usually spaced slightly further away and comes last.

What does a gold band mean?

As a multiplier it means ×0.1; as a tolerance band it means ±5%.

Why does my meter read a different value?

Any reading inside the tolerance band is correct. A 10 kΩ ±5% resistor may measure anywhere from 9.5 kΩ to 10.5 kΩ.

Enter values