Converter
kW to amps converter
Convert between power (kW), current (A) and apparent power (kVA) for single and three phase loads. Set the supply, then convert either way.
Single phase: I = P / (V x pf). Three phase: I = P / (1.732 x line V x pf). kVA = kW / pf.
Converting between power and current
Datasheets quote power in kilowatts. Cables, breakers and the supply are rated in amps. Getting between the two is everyday arithmetic on a job, and all you need is the voltage, the number of phases and the power factor.
The formulas
- Single phase: amps = (kW x 1000) / (voltage x power factor).
- Three phase: amps = (kW x 1000) / (1.732 x line voltage x power factor).
A 7 kW charger on a 230 V single phase supply at unity power factor is about 30.4 A, which is why it goes on a 32 A circuit. At a poorer power factor the same real power draws more current.
kW, kVA and power factor
kW is the real power that does work. kVA is the apparent power the supply has to deliver. They are equal only at a power factor of 1. Motors, transformers and discharge lighting draw current that does not all turn into useful work, so their kVA, and the current in the cable, is higher than the kW suggests. Size conductors and protection on the current, so always convert at the real power factor. Take the result to the cable size calculator.
FAQs
How do you convert kW to amps?
Single phase: amps = (kW x 1000) / (voltage x power factor). Three phase: amps = (kW x 1000) / (1.732 x line voltage x power factor).
What is the difference between kW and kVA?
kW is real power. kVA is apparent power. kVA = kW / power factor. They are equal only when the power factor is 1, so a lower power factor means more current for the same kW.
How many amps is a 7kW EV charger?
About 30.4 A on a 230 V single phase supply, which is why a 7 kW home charger goes on a 32 A circuit.