Ohm's Law Calculator

Physics guide

How to use the Ohm's Law Calculator

Calculate resistance and power from voltage and current. The page also explains the ohm's law and shows a practical example: 12 V and 2 A gives 6 ohms and 24 W.

  1. 1

    Enter your details

    Enter voltage and current, then complete any other fields shown in the calculator.

  2. 2

    Check the calculation

    Review the result alongside the ohm's law: Resistance = voltage / current; power = voltage x current.

  3. 3

    Compare scenarios

    Change one or more inputs to see how they affect the ohm's Law Calculator result before you use the estimate.