kW to Amps Three Phase Converter
Convert kilowatts to amps on a three phase supply. Enter your power, voltage and power factor to get the line current in seconds.
Convert kW to Amps (3 Phase)
Enter the load power, supply voltage and power factor. The calculator returns the current per phase, plus apparent and reactive power.
Three Phase kW to Amps Calculator
I = (kW × 1000) ÷ (√3 × V × PF)
How the Conversion Works
Key points for three phase current
Line-to-Line Formula
I = (kW × 1000) ÷ (1.732 × VLL × PF). Use the voltage measured between any two phases, such as 400V or 415V in the UK.
Line-to-Neutral Formula
I = (kW × 1000) ÷ (3 × VLN × PF). Use this when you know the phase-to-neutral voltage, such as 230V. It gives the same result as the line-to-line formula.
Power Factor Matters
A lower power factor means more current for the same kW. Check the nameplate; motors are often around 0.8 and heaters close to 1.0.
Motors and Efficiency
A motor rated in kW or HP is the shaft output. Dividing by efficiency gives the higher electrical input that the supply must deliver.
kW to Amps 3 Phase Chart
Line current in amps at a power factor of 0.8, using line-to-line voltage.
| Power (kW) | 208V | 230V | 400V | 480V |
|---|---|---|---|---|
| 5 kW | 17.4 A | 15.7 A | 9.0 A | 7.5 A |
| 10 kW | 34.7 A | 31.4 A | 18.0 A | 15.0 A |
| 20 kW | 69.4 A | 62.8 A | 36.1 A | 30.1 A |
| 50 kW | 173.5 A | 156.9 A | 90.2 A | 75.2 A |
| 100 kW | 347.0 A | 313.8 A | 180.4 A | 150.4 A |
kW to Amps Three Phase FAQ
Answers to common questions about converting kilowatts to amps on a three phase supply.
Divide the power in watts by the square root of 3 (1.732) multiplied by the line-to-line voltage and the power factor. In formula form: I = (kW x 1000) / (1.732 x V x PF).
At 400V and a power factor of 0.8, 10 kW draws about 18 amps per phase. At a power factor of 1.0 it draws about 14.4 amps.
Use the value on the equipment nameplate. If it is unknown, 0.8 is a common estimate for induction motors, while resistive loads such as heaters have a power factor close to 1.0.
Yes. For the same power and voltage, a balanced three phase load draws roughly 58% of the current per line compared with a single phase load, which allows smaller cables.
The result is a calculated load current only. Cable and protective device sizing must follow local wiring regulations and be confirmed by a qualified electrician.