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Ohm's law

Enter two known values to solve voltage, current or resistance in a DC circuit.

Ideal DC/resistive V = IR relationships. Reactive AC impedances and component ratings are not modelled.

Leave blank to solve for voltage from current and resistance (V = I × R).

Leave blank to solve for current from voltage and resistance (I = V / R).

Leave blank to solve for resistance from voltage and current (R = V / I).

Results update as you type (enter exactly two values).

Results

Enter exactly two values to solve the third.

Method and assumptions

Relationships: V = I × R and P = V × I (DC, resistive load).

Related calculators

Check the stated method and limits against your installation. Results are calculation aids, not certification.

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Calculation model 2026-11-02.1