Watts to Amps Calculator

WORKED EXAMPLE

Example: the simple DC case

An illustrative 1,200 W electrical load at 120 V DC draws 1,200 ÷ 120 = 10 A. This demonstrates the equation; it is not a suggested device or supply setup.

WORKED EXAMPLE

Example: single-phase AC with power factor

At 120 V RMS and power factor 0.8, an example 1,200 W electrical input requires 1,200 ÷ (120 × 0.8) = 12.5 A. In the reverse direction, 10 A at those same AC assumptions corresponds to 960 W, or 0.96 kW.

Watts and VA answer different questions

For single-phase AC, RMS volts × amps gives apparent power in volt-amperes (VA). Multiplying by power factor gives real input power in watts. Power factor must be greater than zero and at most one here; it is not the efficiency of a charger or motor.

Use electrical input power

Mechanical output watts on a motor are not its electrical input watts. Converting between those requires a separate efficiency assumption. A US 240 V split-phase load uses the single-phase equation, not a three-phase multiplier.

Voltage presets are arithmetic conveniences

The 120 V and 240 V examples do not establish a circuit’s capacity or a safe charging-current setting. This calculator converts units; it does not size breakers, select wiring, or approve an installation.