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Resistor Calculator
Read resistor color bands or calculate the equivalent resistance of two resistors.
Your estimate
Enter measurements and select Calculate.
How this estimate works
Four bands use two significant digits; five bands use three. Multiply the digits by the multiplier, then apply tolerance to find the nominal range. Read with the tolerance band on the right. Series: R1 + R2. Parallel: 1 ÷ (1/R1 + 1/R2). Network mode assumes ideal positive resistors; it does not calculate power ratings or network tolerance.
DigiKey resistor color-code reference
Values are rounded only for display. Calculations stay on this device. No signup required.
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