Free electrical calculators for power work

kW to Amps Calculator

Enter kilowatts, voltage, phase and power factor to get the current, or convert amps back to kW.

The kW to amps calculator converts power in kilowatts into current in amps, and it also converts amps into kW. It works for single-phase, three-phase and DC supplies. You choose the conversion direction, enter the voltage and power factor, and read the current or power result. The calculator runs in your browser, is free, needs no sign-up and uploads nothing. Each result comes with the formula and every step using your numbers, so you can check how the answer was reached, and a table shows the same load at other common voltages, from 208 V up to 600 V for three phase.
Kw to amps calculator example

How to use the kW to amps calculator

  1. Open the Convert drop-down and choose kW to amps or Amps to kW.
  2. Open the Supply type drop-down and choose Three phase AC, Single phase AC or DC.
  3. Enter the Voltage (V). For three-phase supplies, use the line-to-line voltage, such as 208, 400, 415, 480 or 600 V.
  4. Enter the Power factor (PF). Use about 0.8 to 0.9 for motors and generators, and 1 for heaters.
  5. Enter the Power (P) in kW, MW, W or hp when that field appears. For Amps to kW, enter the Current (I) in amps instead.
  6. If the kW value is the shaft output of a motor, open More options and enter the Motor efficiency (η) in %. Leave it at 100 if the kW is the electrical input.
  7. Read the result rows. Only the rows that apply to your chosen mode are shown.

You can start from the example buttons above the form (10 kW at 480 V three-phase, 5 kW at 240 V single-phase, 50 kW at 400 V three-phase, or a 2.2 kW motor at 400 V). The tables under the result show the current at common voltages. Use Copy result to copy the result lines with a link, Copy link to save the exact inputs, or Print / save as PDF to keep a record with the date. Reset restores the starting example.

How do you convert kW to amps?

Divide the power in watts by the voltage and, for AC, by the power factor. For single-phase AC, the current is I = kW × 1,000 ÷ (V × PF). For three-phase AC, it is I = kW × 1,000 ÷ (√3 × V × PF), where √3 is about 1.732. For DC there is no power factor, so I = kW × 1,000 ÷ V.

For example, a 10 kW three-phase load at 480 V with a power factor of 0.85 draws about 14.15 A: 10,000 ÷ (1.732 × 480 × 0.85) ≈ 14.15. The result is the line current. In a balanced three-phase load, each line carries the same current.

Motors are rated by shaft output, which is less than the electrical power they draw. To find the electrical input, divide the output by the efficiency. A 2.2 kW motor at 400 V, with a power factor of 0.82 and 86 % efficiency, draws about 4.503 A. Without the efficiency correction, the current would appear lower than it really is.

How do you convert amps to kW?

Multiply the voltage, the current and the power factor, then divide by 1,000. For single-phase AC, kW = V × I × PF ÷ 1,000. For three-phase AC, kW = √3 × V × I × PF ÷ 1,000. This is the same formula rearranged, so the two directions always agree.

For example, 100 A at 480 V three-phase with a power factor of 0.85 gives about 70.67 kW. Check any result by running it back through the other direction.

Kilowatt to amp conversion at common voltages

The table under the result is a kW to amps conversion table for the load you entered. For 10 kW three phase at PF 0.85 it reads 32.66 A at 208 V, 16.98 A at 400 V, 16.37 A at 415 V, 14.15 A at 480 V and 11.32 A at 600 V: the same power, less current as the voltage rises. To calculate kW to amps for one more voltage, change the voltage field; the table follows.

For the other direction, an amp to kilowatt conversion (amperes to kilowatts) uses the same formula rearranged. Choose Amps to kW and the page becomes an amp to kilowatt calculator and converter: to convert amp into kW, enter the current, voltage and power factor. Whichever way you transfer kW to amps or amp into kW, the steps list the kW to ampere calculation with your numbers.

Worked examples

InputResult
10 kW, 480 V, three phase, PF 0.8514.15 A
5 kW, 240 V, single phase, PF 120.83 A
50 kW, 400 V, three phase, PF 0.980.19 A
2.2 kW, 400 V, three phase, PF 0.82, η 86 %4.503 A
100 A, 480 V, three phase, PF 0.8570.67 kW

Calculated by the tool above with these values.

Frequently asked questions

How many amps is 1 kW?

It depends on the voltage and supply type. At 240 V single-phase with a power factor of 1, 1 kW draws about 4.17 A (1,000 ÷ 240). At 480 V three-phase with a power factor of 0.85, the same 1 kW draws about 1.42 A.

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

At 480 V with a power factor of 0.85, a 10 kW three-phase load draws about 14.15 A. Change the voltage or power factor in the calculator to see the current for your own supply.

How do I convert 100 A to kW?

Select Amps to kW, set the supply type to three-phase, and enter 480 V, 100 A and a power factor of 0.85. The result is about 70.67 kW.

Why does the calculator show a power factor warning?

It appears when the power factor you entered is unusually low. Use 1 for resistive loads and the nameplate power factor for motors, so check the value you typed. Also check the voltage if the current shows a very high warning.

Can I use the calculated current to size a motor circuit?

Use the nameplate full-load current for motor circuits, not the calculated value. Codes use the nameplate figure, so treat this result as an estimate. The note under every result says to verify critical designs against the applicable standard.

Does this calculator work for DC supplies?

Yes. Select DC as the supply type. The power factor is not used, so only the power and voltage matter.

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