Enter your Current (Amps) and Voltage (Volts), then select your Current Type (DC, AC single-phase, or AC three-phase) — and if needed, adjust the Power Factor — to calculate your Power in Watts and Kilowatts, plus the exact formula used for your setup.
Power (Watts)
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Power (Kilowatts)
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Formula Used
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Amps measure electric current (flow of electricity), volts measure voltage (electrical pressure), and watts measure power (rate of energy consumption). Think of amps as water flow, volts as water pressure, and watts as the total work done.
For DC circuits: Watts = Amps × Volts. For AC single-phase: Watts = Power Factor × Amps × Volts. For AC three-phase: Watts = √3 × Power Factor × Amps × Voltage.
Power factor is a measure of how effectively electrical power is used in AC circuits, ranging from 0 to 1. A power factor of 1 means perfect efficiency, while lower values indicate less efficient power usage. It only applies to AC circuits, not DC.
In three-phase systems, line-to-line voltage is measured between any two phases, while line-to-neutral voltage is measured between one phase and the neutral point. Line-to-line voltage is typically √3 times higher than line-to-neutral.
Yes, this calculator works for DC circuits (no power factor needed) and both single-phase and three-phase AC circuits. Simply select the appropriate current type and the calculator will use the correct formula.
Resistive loads (heaters, incandescent bulbs) have a power factor near 1.0. Motors typically range from 0.7 to 0.9. Fluorescent lights are around 0.5 to 0.95. Electronic devices vary widely from 0.5 to 0.9 depending on design.
Divide watts by 1000 to get kilowatts. For example, 1500 watts = 1.5 kilowatts. This calculator automatically shows both values for your convenience.
Converting amps to watts is essential for cable sizing, breaker selection, and determining total system power requirements. It helps ensure electrical safety and proper system design by calculating the actual power consumption from current and voltage values.