Resistance
R = (10 x first digit + second digit) x multiplier
Electrical calculator
Resistor Color Code Calculator
Select resistor bands to calculate nominal resistance.
Calculator
Enter values
Results update automatically as you type.
Result
About this calculator
How it works
Resistor color bands encode significant digits, a multiplier, and tolerance. This tool decodes common four-band resistors.
Formulas
Formulas used
Tolerance
Tolerance is read from the fourth band.
Guide
How to use this calculator
- Choose the mode or component type if the calculator provides one.
- Enter known values and select the units beside each input.
- Read the highlighted result first, then use the table for supporting calculated values.
Reference
What the results mean
Resistance
The nominal resistor value decoded from the bands.
Tolerance
The expected manufacturing range around the nominal value.
FAQ
Resistor Color Code Calculator questions
Can I use different units?
Yes. Select the unit beside each input. The calculator converts values internally before solving.
Are the results suitable for final design?
Use results for education, screening, and early design checks. Verify final work against standards, datasheets, and project requirements.
Why does the result update automatically?
The calculator listens for input changes and recalculates as soon as enough valid values are available.
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