Amps to Watts Calculator

This calculator converts current in amperes to power in watts for both DC and single-phase AC circuits. Knowing how many watts a device uses is essential for comparing running costs, planning generator capacity, designing battery systems, and checking whether a circuit is overloaded. For a DC circuit the formula is P = V times I, where P is power in watts, V is voltage in volts, and I is current in amperes. For a single-phase AC circuit you multiply by the power factor as well: P = V times I times PF. The power factor is a number between 0 and 1 that reflects how efficiently the load uses the current drawn. A kettle, toaster, or electric heater is purely resistive with PF = 1.0, so all the current goes directly into useful heat. A motor or fluorescent light has a lower power factor, typically 0.8 to 0.95, meaning it draws more current than its watt rating alone would imply. You enter the current in amps, supply voltage, and power factor, and the calculator returns the real power in watts and kilowatts along with the apparent power in volt-amps. Select DC mode to calculate without a power factor. For the default values of 10 A, 240 V, and PF 1.0, the power is 2,400.00 W or 2.40 kW. This tool covers single-phase calculations only; three-phase power uses a different formula involving the square root of three.

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