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Amps to kW Calculator

Enter amps, voltage and power factor to get kilowatts and kVA for a single phase, three phase or DC load.

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Amps to kW means multiplying the current by the voltage and the power factor, then dividing by 1,000; on three phase the result is also multiplied by √3. That makes 30 A at 480 V three phase with a power factor of 0.85 equal to 21.2 kW. This calculator starts in three phase, since that is where amps-to-kilowatts questions come up most, and you can switch to single phase or DC. Next to the kW it shows apparent power in kVA and reactive power in kvar. In motor mode it also estimates the shaft output in kW and horsepower from the efficiency you type. A table under the result gives the kW and kVA at each standard voltage.
Amps to kw example

How to use the Amps to kW Calculator

  1. In The load is, keep “A general load”, or choose “A motor (show shaft output)” to see the mechanical output too.
  2. Pick the Supply type. The list starts with “Three phase AC”; “Single phase AC” and “DC” follow.
  3. Enter Current (I) in amps, for example a measured current or a nameplate value.
  4. Enter the Voltage (V). Typical values are 208, 240, 480 and 600, and three phase always takes the line-to-line voltage.
  5. Set the Power factor (PF): about 0.8 to 0.9 for motors and 1 for heaters. DC hides this box.
  6. In motor mode, enter Motor efficiency (%) from the nameplate, typically 85 to 95 % for industrial motors.
  7. Read Power (P) in kilowatts, then Apparent power (S) and Reactive power (Q). A motor also gets Motor shaft output and Motor shaft output in horsepower, plus a note that both are estimates.

Four example buttons cover common cases, from “30 A at 480 V three phase” to “32 A at 230 V single phase”. “Copy result” copies the numbers, “Copy link” copies a link that reopens your inputs, “Print / save as PDF” prints them, and Reset brings back the defaults.

Changing any field updates the result rows, the steps and the tables straight away, and Copy link keeps your exact inputs in the address so you can share or reopen the calculation.

How do you convert amps to kW?

Multiply amps by volts and by the power factor, then divide by 1,000. For single phase AC that is kW = A × V × PF ÷ 1,000, and for DC the power factor drops out. An EV charger drawing 32 A on 230 V single phase with PF 1 works out to 7.36 kW, the same figure the tool returns.

  1. Multiply the current by the voltage: 32 A × 230 V = 7,360 VA.
  2. Multiply by the power factor: 7,360 × 1 = 7,360 W.
  3. Divide by 1,000: 7.36 kW.

On DC, 100 A at 48 V is simply 4.8 kW. With a power factor below 1 the kW is lower than the kVA, and the gap shows up as reactive power.

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

For three phase, kW = √3 × A × V × PF ÷ 1,000, with V the line-to-line voltage and √3 about 1.732. A load of 30 A at 480 V and PF 0.85 is 21.2 kW, with 24.94 kVA of apparent power and 13.14 kvar of reactive power. The tool uses this formula by default.

Current and voltagePFPower (kW)Apparent power (kVA)
30 A, 480 V0.8521.224.94
14 A, 460 V0.849.3711.15
100 A, 208 V0.9534.2336.03
200 A, 480 V0.9149.65166.28

The 30 A row at the other standard voltages gives 9.19 kW at 208 V, 10.6 kW at 240 V and 26.5 kW at 600 V.

How do I get motor shaft output from amps?

Calculate the electrical input in kW, then multiply by the motor efficiency. A motor drawing 14 A at 460 V three phase with PF 0.84 takes 9.37 kW; at 91 % efficiency its shaft delivers about 8.53 kW, or 11.43 mechanical horsepower. Both values are estimates, because efficiency changes with load.

  1. Choose “A motor (show shaft output)” in The load is.
  2. Enter the measured or nameplate current, the voltage and the power factor.
  3. Type the efficiency from the nameplate into Motor efficiency (%).
  4. Read Motor shaft output in kW and Motor shaft output in horsepower.

Worked examples

InputResult
30 A, 480 V, three phase, PF 0.8521.2 kW, 24.94 kVA
14 A, 460 V, three phase, PF 0.849.37 kW, 11.15 kVA
100 A, 208 V, three phase, PF 0.9534.23 kW, 36.03 kVA
32 A, 230 V, single phase, PF 17.36 kW, 7.36 kVA

Calculated by the tool above; open it with the same values to see each step.

Questions, briefly answered

What is 200 amps in kW?

At 240 V single phase with PF 1, 200 A is 48 kW. On a 208 V three phase supply with PF 1 it is 72.05 kW, and at 480 V with PF 0.9 it is 149.65 kW.

How many amps is 1 kW?

At 240 V with a power factor of 1, one amp carries 0.24 kW, so 1 kW is about 4.17 A. Use the kW to Amps Calculator to work in that direction.

What is the difference between kW and kWh?

A kW is power, the rate of energy use at a moment. A kWh is energy: power multiplied by time, so a 2 kW load for 3 hours uses 6 kWh.

How do I calculate electricity cost from amps?

Convert the amps to kW, multiply by the hours of use for kWh, then multiply by the price per kWh on your bill. The Amps to Watts Calculator does those steps when you enter hours and your price.

Why is kW lower than kVA?

kVA is volts times amps, and kW is the part of it that does real work. With a power factor of 0.85, 24.94 kVA delivers 21.2 kW.

What power factor should I enter?

Use the value from the nameplate or a measurement when you have one. Otherwise the help text suggests about 0.8 to 0.9 for motors and 1 for heaters and other resistive loads.