This series and parallel resistance calculator finds the total (equivalent) resistance of a resistor network. Enter your resistors above and choose series or parallel.
Formulas
Series: Rtotal = R1 + R2 + R3 + ... Parallel: 1 ÷ Rtotal = 1/R1 + 1/R2 + 1/R3 + ...
Examples
- Series 10 + 20 + 30 = 60 Ω
- Parallel 10 & 20: 1/R = 0.1 + 0.05 → R = 6.67 Ω
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Frequently Asked Questions
How do I calculate total resistance in series?
Add the resistor values together. Three resistors of 10, 20, and 30 ohms in series total 60 ohms.
How do I calculate parallel resistance?
Add the reciprocals of each resistor, then take the reciprocal of the sum. Two 10-ohm resistors in parallel give 5 ohms.
Is parallel resistance always lower?
Yes. The equivalent parallel resistance is always smaller than the smallest resistor in the group.