FREE · CALCULATORS & CONVERTERS
Ohm’s Law Calculator.
Find voltage, current, resistance and power from any two electrical values.
Direct current relationship V = I × R. Power = V × I. Local arithmetic only. This is a quantity or geometry estimate, not a code check and not a substitute for a licensed professional.
- Voltage
- 10 V
- Current
- 2 A
- Resistance
- 5 Ω
- Power
- 20 W
Voltage = current × resistance. Power = voltage × current.
How to use Ohm’s Law Calculator
Choose the value to find, enter the two known values and read voltage, current, resistance and power.
How it works
Find voltage, current, resistance and power from any two electrical values. Direct current relationship V = I × R. Power = V × I. Local arithmetic only. This is a quantity or geometry estimate, not a code check and not a substitute for a licensed professional.
Example
2 A through 5 Ω gives 10 V and 20 W.
Questions about Ohm’s Law Calculator
Is Ohm’s Law Calculator free, and do I need an account?
Yes. This tool is free to use in your browser without an account. Processing takes place on your device.
What are the limits and what should I check?
Direct current relationship V = I × R. Power = V × I. Local arithmetic only. This is a quantity or geometry estimate, not a code check and not a substitute for a licensed professional. Review the result before using it in your work.
Is my input sent to a server?
Your input is processed in your browser and is not uploaded by this tool. Files and pasted text are cleared when the page is refreshed. Normal website requests are still required to load the page and its libraries. Read the privacy explanation.