Power & Wattage Calculator
Enter any two known values to instantly calculate the Power, Voltage, Current, and Resistance.
Ohm's Law & Watt's Law
Electrical circuits are governed by mathematical rules that relate Power (P), Voltage (V), Current (I), and Resistance (R). If you know any two of these values, you can always calculate the other two.
- Power (Watts): The rate at which electrical energy is transferred. (e.g., A 1500W space heater).
- Voltage (Volts): The electrical pressure pushing the electrons. (Standard US wall outlets are 120V).
- Current (Amps): The volume of electrons flowing through the wire. (Standard US breakers are 15A or 20A).
- Resistance (Ohms): The opposition to the flow of current.
Formulas used in this calculator: Power = Volts × Amps. Voltage = Amps × Resistance.