Hardware tool

Ohm's Law Calculator

Solve voltage, current, resistance, and power from any two known electrical values.

Runs in your browser
Ohm's Law Calculatorupdates live
Result
Voltage
12 V
Current
2 A
Resistance
6 Ω
Power
24 W
Energy in one hour
24 Wh

Choose which two values are known. The unused input is ignored. Real components may be nonlinear and change resistance with temperature.

How to use this ohm's law calculator

  1. Enter the known electrical values with the correct units, then check the proposed current, voltage, resistance, or wire result.
  2. Review the calculated totals, units, and assumptions. Check the inputs and units before relying on the result.
  3. Change one input at a time to compare another case, then copy or save the result you plan to use.

About this ohm's law calculator

Use the Ohm's Law Calculator to solve voltage, current, resistance, and power from any two known electrical values. Each control affects a specific part of the result.

You can also use it to compare results after changing one input.

Example

Enter 12 volts and 6 ohms to calculate 2 amps and 24 watts using Ohm's law.

Common uses

  • solve voltage, current, resistance, and power from any two known electrical values
  • compare results after changing one input
  • save an estimate for planning or comparison