Amps to kW Calculator
Convert amperes to kilowatts for single phase and three phase systems. Results include both kW and watts.
Convert Amps to kW
Result
—
Power (kW)
—
Power (Watts)
Formula
Single Phase:
kW = (Amps × Volts × Power Factor) ÷ 1000
Three Phase:
kW = (√3 × Amps × Volts × Power Factor) ÷ 1000
Where √3 ≈ 1.732. Power factor defaults to 1 for purely resistive loads.
Example Calculations
Single Phase: 30A at 240V, PF = 0.9
kW = (30 × 240 × 0.9) ÷ 1000
kW = 6480 ÷ 1000 = 6.48 kW (6,480 W)
kW = 6480 ÷ 1000 = 6.48 kW (6,480 W)
Three Phase: 20A at 415V, PF = 0.85
kW = (1.732 × 20 × 415 × 0.85) ÷ 1000
kW = 12,210 ÷ 1000 = 12.21 kW
kW = 12,210 ÷ 1000 = 12.21 kW
Practical Notes
- Use PF = 1.0 for resistive loads such as water heaters and ovens.
- For motors, check the nameplate — PF is often listed as 0.75–0.90.
- Three phase gives more power for the same current — ideal for heavy industrial loads.
- kVA = kW ÷ Power Factor. Equipment rated in kVA (UPS, generators) uses this.
- Always measure amps with a clamp meter rather than reading the breaker rating.
Frequently Asked Questions
How do I convert amps to kW?
Single phase: kW = (A × V × PF) ÷ 1000. Three phase: kW = (1.732 × A × V × PF) ÷ 1000. You need to know your voltage and power factor for an accurate result.
How many kW is 30 amps at 240V?
At PF = 1 single phase: kW = (30 × 240 × 1) ÷ 1000 = 7.2 kW. At PF = 0.9 it would be 6.48 kW. If three phase at 240V and PF = 1: kW = 1.732 × 30 × 240 ÷ 1000 = 12.47 kW.
What is the difference between kW and kVA?
kW (kilowatts) is real power — the actual work done. kVA (kilovolt-amperes) is apparent power. The relationship is: kW = kVA × Power Factor. For purely resistive loads at PF = 1, kW and kVA are equal.