Power Calculator
Calculate electrical power in watts by entering voltage and current — the power calculator applies P = V × I instantly.
Power
—W
How to Use This Calculator
Enter the voltage across your component or circuit in volts, and the current flowing through it in amps. Click Calculate Power to get the power dissipated or consumed in watts. If you know the current in milliamps, divide by 1000 first (e.g. 150 mA = 0.15 A).
Formula
Electrical power is the rate of energy transfer. For a DC circuit:
P = V × I
Power can also be expressed as P = I²R or P = V²/R using Ohm's Law substitutions.
Example
Scenario: A 12V motor drawing 2.5 A
P = V × I = 12 × 2.5
P = 30 W
Small circuit: 3.3V microcontroller drawing 80 mA (0.08 A)
P = 3.3 × 0.08
P = 0.264 W (264 mW)
P = V × I = 12 × 2.5
P = 30 W
Small circuit: 3.3V microcontroller drawing 80 mA (0.08 A)
P = 3.3 × 0.08
P = 0.264 W (264 mW)