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Ohm’s Law Calculator

Solve voltage, current, resistance and power from exactly two known positive values for a DC or resistive circuit.

Enter exactly two known values; clear the other two. Use Reset to return to the 12 V / 2 A example.

Enter your values, then calculate. Results clear when an input changes.

Formula and units

V = I × R; P = V × I = I² × R = V² / R.

How to use these results

Enter exactly two values and leave the other fields empty. All six pairs are supported. Assumes a DC or resistive load; it does not model AC impedance, reactive loads, nonlinear devices or component temperature changes. Positive known values avoid ambiguous zero-power pairs.

Verify critical electrical work with a qualified professional and applicable manufacturer instructions.

Worked example

12 V and 2 A give 6 Ω and 24 W. Entering 6 Ω and 24 W returns the same 12 V and 2 A.

Reference

Formula background: Fluke — Electrical measurements: units, devices and formulas. The assumptions and input validation above define this calculator’s scope.

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