Ohm's Law Calculator
Voltage, current, resistance and power from any two.
Reviewed by the Calculation Machine team · How we check our maths
Your values
ⓘ Live results
Results
- Voltage
- 12 V
- Current
- 2 A
- Resistance
- 6 Ω
- Power
- 24 W
Working
- 1V = I × R = 2 × 6 = 12 V
Quick answer
Ohm's law states V = I × R, and power follows as P = V × I.
The formula
V = I·R, P = V·I
How to use the Ohm's Law Calculator
- 1Fill in any two of the four boxes.
- 2Leave the unknowns blank.
- 3Read all four values.
Frequently asked questions
What is one ohm?
The resistance that lets one amp flow when one volt is applied across it.
Does Ohm's law apply to AC?
For resistive loads yes. Reactive circuits need impedance, which accounts for phase between voltage and current.
About this calculator
- Built and reviewed by the Calculation Machine team · How we build and test calculators
- Report an error