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Ohm’s Law Calculator

Enter two known values to calculate voltage, current, resistance, and power.

Your measurements

Choose a unit beside each measurement. Switching units preserves your dimensions.

Your estimate

Enter measurements and select Calculate.

How this estimate works

V = I × R and P = V × I. Enter two positive known values. Applies to DC resistive circuits, or RMS values in a purely resistive AC load. Does not model reactance, phase angle, or non-ohmic devices.

Values are rounded only for display. Calculations stay on this device. No signup required.

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