This watts to amps calculator converts electrical power into the current a device draws, which is one of the most practical electrical calculations around the home and workshop. Appliances and equipment are usually labelled in watts, but the things that limit a circuit, the fuses, breakers, cables and plugs, are all rated in amps, so being able to turn a wattage into a current tells you whether a circuit can safely handle a load. The conversion is straightforward: the current in amps equals the power in watts divided by the voltage, and for alternating current you also divide by the power factor, a number between 0 and 1 that allows for current that flows without doing useful work. You enter the power and the voltage, and adjust the power factor if needed, leaving it at 1 for direct current or simple resistive loads like heaters and incandescent bulbs, or lowering it to around 0.8 for motors and some electronics. The calculator then returns the current in amps. In New Zealand, use 230 volts for anything running off a wall socket, which makes a 2300 watt appliance draw about 10 amps, near the safe limit of a standard outlet. Enter the power and voltage to see the current straight away, and check it against your circuit's rating.
Use power factor 1 for DC or resistive loads, around 0.8 for motors. New Zealand mains is 230 V. Estimate only, not an electrical design tool.
The calculator divides the power in watts by the voltage, and then by the power factor, to give the current in amps. For direct current or purely resistive loads the power factor is 1, so the current is simply watts divided by volts.
A 2300 watt heater on 230 volt mains with a power factor of 1 draws 2300 divided by 230, which is 10 amps. A motor of the same rating with a power factor of 0.8 would draw about 12.5 amps.
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