Ohm's Law Calculator

Find current and power from voltage and resistance. Free, private, and runs entirely in your browser.

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Enter values and press Calculate to see the result here.

How this is calculated

Ohm's law relates voltage, current and resistance. Power follows from voltage and current.

I = V ÷ R

P = V² ÷ R

What units are used? Volts, ohms, amps and watts.

Does it work for AC? For purely resistive loads, yes, using RMS values.