Amps to kW Calculator
Turn a measured current into real power in kilowatts. Enter the amps with the system voltage, phase, and power factor.
When to use it
Clamp meters on site read current in amps, not power. When you measure the draw on a running distribution board or a single circuit, this converter turns that reading into real power in kilowatts, so you can compare it against a generator rating or a load schedule. Keep the power factor close to the actual load for an accurate figure.
How it is calculated
For three phase, kW = (1.732 x volts x amps x power factor) / 1000. For single phase, drop the 1.732.
At 400 V, 1 A, power factor 0.8, three phase: kW = (1.732 x 400 x 1 x 0.8) / 1000 = 0.55 kW.
Common conversions
| Current (A) | Real power (kW) |
|---|---|
| 16 A | 8.9 kW |
| 32 A | 17.7 kW |
| 63 A | 34.9 kW |
| 100 A | 55.4 kW |
| 200 A | 110.9 kW |
| 400 A | 221.7 kW |
Frequently asked questions
How do you convert amps to kW?
Multiply the voltage, amps, and power factor, then divide by 1000. For three phase also multiply by 1.732: kW = (1.732 x volts x amps x power factor) / 1000.
Why multiply by 1.732 for three phase?
1.732 is the square root of 3. It relates the line voltage and current to the total power across the three conductors of a three phase supply.
What is the difference between kW and kVA?
kW is real (working) power; kVA is apparent power, the total the supply has to deliver. They are linked by the power factor: kW = kVA x power factor.
Does the power factor change the kW result a lot?
Yes. Real power is directly proportional to power factor, so a reading taken at 0.7 gives a noticeably lower kW than the same current at 0.9. Use the actual load power factor where you can.
Is this the same as the power a generator must supply?
It is the real power in kW. A generator is rated in kVA, so divide the kW by the power factor to see the apparent power the set actually has to deliver.