Ohm's Law Calculator
Voltage, current, resistance and power from Ohm's law.
Enter your values
ⓘ Live results
Results
- Voltage
- 20 V
- Power
- 40 W
- Current
- 2 A
- Resistance
- 10 Ω
Quick answer
V = I x R, and P = V x I.
V = IR, P = VI
How to use the Ohm's Law Calculator
- 1Enter the current flowing through the circuit.
- 2Enter the resistance of the load.
- 3Read the resulting voltage and power dissipated.
Worked example
Using the values the calculator loads with:
Inputs
- Current2 A
- Resistance10 ohms
Results
- Voltage20 V
- Power40 W
- Current2 A
- Resistance10 Ω
Frequently asked questions
What if I know voltage and resistance instead?
Rearrange as I = V/R; this tool takes current and resistance as inputs since they set voltage and power directly.
What is Ohm's law used for?
It underlies almost all basic circuit design and troubleshooting for resistive loads.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.