This calculator determines the total effective resistance of any number of resistors in series and parallel configurations.
Series Resistance Calculator
Enter the resistor values separated by commas.
Series Resistance Formula
Rtotal = R1 + R2 + R3 +…. + Rn
Example Calculation
Consider four resistors in parallel: 1 Ω, 6 Ω, 15 Ω and 100 Ω. The total effective resistance is 122 Ω.
If you have two resistors – one large and the other small in parallel, the effective resistance is closer to the larger value. Take for instance 1 Ω and 1000 Ω in series. The effective resistance is 1001 ≈ 1000 Ω.
Parallel Resistance Calculator
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.
Series and Parallel Resistance Calculator
Enter the series and parallel resistor values in two separate fields separated by commas.
Series and Parallel Resistance Formula
Rparallel = (1/R1 + 1/R2 + 1/R3 +…. + 1/Rn)-1
Rseries = R1 + R2 + R3 +…. + Rn
Rtotal = Rparallel + Rseries
Example Calculation
Consider three resistors in parallel: 1 Ω, 3 Ω, and 5 Ω and two resistors in series 1 Ω and 2 Ω
The total parallel resistance Rparallel = 0.652 Ω
The total series resistance Rseries = 3 Ω
The total effective resistance Rtotal = 3.652 Ω