Total Resistance Calculator

This calculator determines the total effective resistance of any number of resistors in parallel.

Enter the resistor values separated by commas.

Parallel Resistance Formula

Rtotal = (1/R1 + 1/R2 + 1/R3 +…. + 1/Rn)-1

Example Calculation

Consider four resistors in parallel: 1 Ω, 6 Ω, 15 Ω and 100 Ω. The total effective resistance is 0.80 Ω.

If you have two resistors – one large and the other small in parallel, the effective resistance is closer to the smaller value. Take for instance 1 Ω and 100 Ω in parallel. The effective resistance is 0.99 ≈ 1 Ω.