Series parallel resistance

Combine a list of resistances in one series or parallel group, with explicit Ω, kΩ and MΩ units.

Your input

Outputs are cleared when the input changes.

Result

Enter your data or use the example, then run the tool.

Worked example

100 Ω and 200 Ω in series give 300 Ω.

Two 100 Ω resistors in parallel give 50 Ω; a zero-ohm parallel branch makes equivalent resistance zero.

Method

Series resistance is ΣR. Parallel resistance is 1/Σ(1/R), using normalized values to avoid reciprocal overflow.

Inputs convert to ohms before combination. A zero-ohm parallel branch is handled without dividing by zero.

Limits

1–100 finite non-negative resistances. Very large or small scales remain subject to floating-point limitations.

No arbitrary circuit topology, tolerance analysis, current allocation or guaranteed combined wattage.

Sources

OpenStax: resistors in series and parallel

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