Ohms Law Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserBasic
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter any two of voltage, current or resistance.
- Press Calculate for the remaining values and the power.
How it works
Ohm's law links voltage (V), current (I) and resistance (R): V = I × R. Power is P = V × I.
Knowing any two of the three lets you find the rest.
Worked example
12 V and 2 A. R = 12 ÷ 2 = 6 Ω, and power = 12 × 2 = 24 W.
Frequently asked questions
What units are used?
Volts, amps, ohms and watts.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.