Electrical Power Calculator
Calculate power in watts from voltage and current, with kilowatts and horsepower.
Results update as you type.
About this calculator
Electrical power is the rate of energy use: P = V × I. For AC loads a power factor below 1 reduces the real power to P = V × I × PF. This calculator returns the power in watts, kilowatts and mechanical horsepower (1 hp = 745.7 W).
Frequently asked questions
What is the electrical power formula?
Real power in watts is P = V × I × PF. For DC or a resistive load the power factor is 1, so power is simply voltage times current.
How many watts in a horsepower?
One mechanical horsepower equals 745.7 watts, so a 1492 W load is about 2 hp. Divide watts by 745.7 to convert.
How is the running cost worked out?
Daily energy is power (kW) × hours per day, in kWh. Multiply by 30 days and your price per kWh to estimate the monthly cost.
Results are estimates for general guidance only, not financial, medical or tax advice.