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