kW to amps converter
Convert kilowatts to amps, or amps to kilowatts, on a single-phase or three-phase supply.
Uses the UK's declared mains voltage of 230 volts between phase and neutral, from the Electricity Safety, Quality and Continuity Regulations.
Show the workings
| Step | Sum | Answer |
|---|---|---|
| Current | 3,000 W ÷ (230 V × 1 power factor) | 13.043 A |
What this leaves out or assumes
- UK mains is declared as 230 volts between phase and neutral. The real voltage can be a little higher or lower.
- A power factor of 1 suits heaters and kettles. Motors and some electronics have a lower one.
Where the figures come from
- Declared voltage of a low voltage electricity supply in Great Britain: 230 V. Source: The Electricity Safety, Quality and Continuity Regulations 2002, regulation 27. Checked 13 November 2026.
kW to amps table
| Power | Single phase | Three phase, each phase |
|---|---|---|
| 1 kW | 4.3 A | 1.4 A |
| 2 kW | 8.7 A | 2.9 A |
| 3 kW | 13 A | 4.3 A |
| 7 kW | 30.4 A | 10.1 A |
| 11 kW | 47.8 A | 15.9 A |
| 22 kW | 95.7 A | 31.9 A |
The sums
Single phase: amps = watts ÷ (volts × power factor). At 230 V and a power factor of 1, a 3 kW kettle draws 13 amps.
Three phase: amps = watts ÷ (√3 × voltage between phases × power factor). The voltage between phases is 230 × √3, which is 398.4 V, often rounded to 400 V. The current is shared across three phases, so it is a third of what one phase would carry.
Power factor is 1 for things that only heat, such as kettles and heaters. Motors and some electronics have a lower power factor and draw more current for the same power. For sizing cables or fuses, ask an electrician.