This electrical power calculator finds power using Watt’s law. Enter any two of voltage, current and resistance to get the power (P = VI = I²R = V²/R) and the remaining quantities.
Electrical Power Calculator
Formula
P = V × I = I² × R = V² / R
How to Use This Calculator
- Enter any two of voltage, current and resistance.
- Click Calculate to get the power in watts.
Worked Example
For V = 230 V and I = 5 A, power P = V × I = 230 × 5 = 1150 W.
Frequently Asked Questions
What is the formula for electrical power?
Electrical power P = V x I, which can also be written as P = I squared x R or P = V squared / R.
What is the unit of power?
The SI unit of power is the watt (W); 1 W = 1 joule per second.
How do you calculate power from current and resistance?
Use P = I squared x R, where I is current and R is resistance.