kW to Amps Calculator (Single-Phase, Three-Phase and DC)

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Updated October 27, 2026

Knowing the current a load draws is the first step in choosing breakers, cables and contactors. The formula depends on whether the supply is DC, single-phase or three-phase — see single-phase vs three-phase power and how to calculate three-phase power. This free kW to amps calculator solves for whichever value you leave blank and shows the formula and steps.

calculated
Type in any field to change it. Press × on a value to calculate that field instead.

How to use the kW to amps calculator

  1. Enter the power in kW (or switch to W or hp).
  2. Choose three-phase, single-phase or DC.
  3. Enter the voltage and power factor (use 1 for DC or purely resistive loads).

The calculator gives the current. It works in reverse too — enter amps and press × on Power to find kW.

KW to amps formulas

System Current
DC I = P ÷ V
Single-phase AC I = P ÷ (V × PF)
Three-phase AC I = P ÷ (√3 × VL × PF)

P is in watts. For a motor, use the electrical input power (rated output ÷ efficiency).

kW to amps chart

kW 230 V 1-ph (PF 1) 230 V 1-ph (PF 0.85) 415 V 3-ph (PF 0.85) 400 V 3-ph (PF 0.85)
0.5 2.2 A 2.6 A 0.8 A 0.8 A
1 4.3 A 5.1 A 1.6 A 1.7 A
1.5 6.5 A 7.7 A 2.5 A 2.5 A
2 8.7 A 10.2 A 3.3 A 3.4 A
3 13.0 A 15.3 A 4.9 A 5.1 A
5 21.7 A 25.6 A 8.2 A 8.5 A
7.5 32.6 A 38.4 A 12.3 A 12.7 A
10 43.5 A 51.2 A 16.4 A 17.0 A
15 65.2 A 76.7 A 24.6 A 25.5 A
22 95.7 A 112.5 A 36.0 A 37.4 A
37 160.9 A 189.3 A 60.6 A 62.8 A
55 239.1 A 281.3 A 90.0 A 93.4 A
75 326.1 A 383.6 A 122.8 A 127.4 A
100 434.8 A 511.5 A 163.7 A 169.8 A

Choosing a breaker and cable

The calculated current is the running current. When selecting protection and cable:

  • Choose a breaker rated above the running current (often the next standard size, such as 16 A, 20 A, 25 A, 32 A).
  • Check the cable’s current-carrying capacity for its installation method.
  • Allow for motor starting current and check the voltage drop.
  • Follow local wiring regulations.

Single-phase vs three-phase

For the same power, a three-phase circuit carries much less current per conductor than a single-phase one, which is why large motors and buildings use three-phase supplies. 10 kW is 43.5 A at 230 V single-phase but only 16.4 A per line at 415 V three-phase (PF 0.85).

Common voltages

Region Single-phase Three-phase
India, UK, Europe, Australia 230–240 V 400–415 V
USA, Canada (residential) 120 / 240 V 208 V or 480 V
Japan 100 V 200 V

Frequently asked questions

How many amps is 1 kW?

At 230 V single-phase and unity power factor, about 4.35 A. At 415 V three-phase with 0.85 PF, about 1.64 A.

What is the formula for kW to amps in three-phase?

I = P ÷ (√3 × V × PF), with P in watts and V the line-to-line voltage.

How many amps does a 10 kW three-phase load draw at 415 V?

About 16.4 A at 0.85 power factor.

Do I use phase or line voltage for three-phase?

Use the line-to-line voltage (for example 400 V or 415 V) with the √3 formula.

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