Ohm's Law Calculator
Solve for voltage, current, resistance, or power. Enter any two values.
Inputs
Results
Power
1200.0000 W
| Voltage | 120.0000 V |
|---|---|
| Current | 10.0000 A |
| Resistance | 12.0000 Ω |
| Power | 1200.0000 W |
How It Works
Ohm's Law: V = I x R Power: P = V x I (and also P = I²R or V²/R, depending on what you know) Plug in any two of V, I, R, and P; the tool solves for the other two.
Example
120 V and 10 A: R = 120/10 = 12 ohms, P = 120 x 10 = 1200 W.
Frequently Asked Questions
Can I enter all four values?
You can. It will solve from the first two it finds. If you fill all four, it just shows what you entered.
Does this apply to AC circuits?
Yes for resistive loads (heaters, incandescent). For motors and other reactive loads, you need impedance (Z) instead of R.
These numbers are for reference only. We are not liable for any decisions you make or how you use these results in the real world. Check the current NEC and your local codes, and have a licensed electrician sign off before you install or buy. Full disclaimer