kW to Amps Calculator
Convert kilowatts to amperes using voltage. This calculator converts power in kilowatts (kW) to current in amps (A) for DC, single-phase AC, and three-phase AC circuits. The formula is Amps = (kW x 1000) / Volts.
How to Convert kW to Amps
- Multiply the kilowatts by 1000 to convert to watts.
- For DC: divide the watts by the voltage to get amps.
- For single-phase AC: divide watts by (voltage x power factor).
- For three-phase AC: divide watts by (sqrt(3) x voltage x power factor).
Formula
DC: Amps = (kW x 1000) / Volts
AC (single-phase): Amps = (kW x 1000) / (Volts x PF)
AC (three-phase): Amps = (kW x 1000) / (sqrt(3) x Volts x PF)
Example Calculation
Convert 5 kW to amps at 240V DC:
Amps = (5 x 1000) / 240 = 5000 / 240 = 20.83A
Convert 5 kW to amps at 240V AC (PF = 0.85):
Amps = (5 x 1000) / (240 x 0.85) = 5000 / 204 = 24.51A
kW to Amps Reference Table (DC)
| Power | Voltage | Current |
|---|---|---|
| 1 kW | 120V | 8.33A |
| 1 kW | 240V | 4.17A |
| 2 kW | 240V | 8.33A |
| 3 kW | 240V | 12.50A |
| 5 kW | 240V | 20.83A |
| 7.5 kW | 240V | 31.25A |
| 10 kW | 240V | 41.67A |
| 5 kW | 480V | 10.42A |
| 10 kW | 480V | 20.83A |
Frequently Asked Questions
How many amps is 1 kW at 240V?
1 kW at 240V DC equals 4.17 amps (1000W / 240V = 4.17A).
What is the relationship between kW and amps?
Kilowatts measure power (rate of energy use), while amps measure current (flow of electrons). They are related through voltage: kW = Amps x Volts / 1000.
Why do I need voltage to convert kW to amps?
Power (kW) equals voltage times current. Without knowing the voltage, you cannot determine the current from power alone.
What power factor should I use?
Resistive loads (heaters, incandescent bulbs) have PF close to 1.0. Motors typically have PF of 0.7-0.9. If unsure, 0.8 is a common assumption for mixed loads.
How do I size a circuit breaker using this calculation?
Calculate the amps, then select a breaker rated at 125% of the continuous load. For example, a 20A load needs a 25A breaker (use the next standard size: 30A).