Watts to Amps Calculator
Convert watts to amps (or amps to watts) for DC, AC and three-phase.
About this tool
Choose watts to amps or amps to watts, pick DC, single-phase or three-phase AC, and enter the voltage (or pick a preset such as 12 V, 120 V or 230 V). For AC, add the power factor. The tool shows current, real power, apparent power and energy per hour.
The formulas
Power, current and voltage are linked by P = V ร I for DC, so amps = watts รท volts: a 60 W device on a 12 V battery draws 5 A. On AC, only part of the current may do useful work, measured by the power factor (PF): 1 for resistive loads like kettles and heaters, about 0.8โ0.95 for motors, compressors and many power supplies. Single-phase: amps = watts รท (PF ร volts), so a 1,500 W kettle draws 6.5 A at 230 V or 12.5 A at 120 V. Three-phase, using line-to-line voltage: amps = watts รท (โ3 ร PF ร volts), so a 10 kW load at 400 V with PF 0.85 draws about 17 A per phase. Apparent power (VA or kVA = volts ร amps) is what generators, UPS units and transformers are rated in. Honest limits: motors draw several times their running current at start-up; breaker and cable sizes must follow local wiring regulations and continuous-load margins. This is not electrical advice, and mains work belongs with a qualified electrician. The Ohm's law calculator and the voltage drop calculator are related.
Frequently asked questions
How many amps is 1,000 watts?
About 4.3 A at 230 V, 8.3 A at 120 V and 83 A at 12 V DC (with a power factor of 1).
How do I convert amps to watts?
Multiply amps by volts (and by the power factor for AC). 13 A at 230 V is 2,990 W.
What is power factor?
The ratio of real power (W) to apparent power (VA). Resistive loads are 1; motors and electronics are often 0.8 to 0.95.
How do I calculate three-phase current?
Divide watts by โ3 ร power factor ร line-to-line voltage.
Is my data sent anywhere?
No. Everything is calculated in your browser, and nothing is stored or sent.