Enter any two of kVA, power factor, or horsepower to calculate the missing value. This conversion uses HP = (kVA × PF) / 0.746 and kW = kVA × PF.
kVA to Hp Formula
The calculator converts apparent power (kVA) to mechanical horsepower using the power factor and motor efficiency. If you enter volts and amps instead, kVA is derived first.
hp = kVA × PF × (η / 100) ÷ 0.7457
If you start from volts and amps:
Single-phase kVA = V × A ÷ 1000 Three-phase kVA = √3 × V × A ÷ 1000
- hp – mechanical (shaft) horsepower output
- kVA – apparent power in kilovolt-amperes
- PF – power factor, between 0 and 1
- η – motor efficiency in percent
- 0.7457 – kilowatts per mechanical horsepower
- V, A – line-to-line voltage and line current for three-phase; supply voltage and current for single-phase
Set efficiency to 100% if you only want to convert electrical kW to hp without motor losses. Use 1.00 for power factor when you are working with a purely resistive load or when kVA already equals kW.
Reference Tables
Use these as starting values when a nameplate is not available.
| Load type | Typical PF | Typical efficiency |
|---|---|---|
| Resistive heater | 1.00 | 100% |
| Induction motor, fully loaded | 0.85 – 0.90 | 88 – 95% |
| Induction motor, half loaded | 0.70 – 0.80 | 82 – 90% |
| Small fractional-hp motor | 0.60 – 0.75 | 60 – 75% |
| Generator (apparent rating) | 0.80 | n/a |
| kVA | hp at PF 0.80, η 90% | hp at PF 1.00, η 100% |
|---|---|---|
| 1 | 0.97 | 1.34 |
| 5 | 4.83 | 6.71 |
| 10 | 9.66 | 13.41 |
| 25 | 24.14 | 33.53 |
| 50 | 48.28 | 67.05 |
| 100 | 96.55 | 134.10 |
Worked Example and FAQ
Example: A 10 kVA supply feeds a motor at PF 0.85 and 90% efficiency.
- Input kW = 10 × 0.85 = 8.5 kW
- Output kW = 8.5 × 0.90 = 7.65 kW
- hp = 7.65 ÷ 0.7457 ≈ 10.26 hp
Why is hp lower than kVA? kVA is apparent power. Only the portion that aligns with voltage (PF × kVA) does real work, and the motor loses more of that to heat and friction before it reaches the shaft.
Should I use 0.7457 or 0.746? Both are common. The calculator uses 0.745699872 kW per mechanical horsepower. For metric (PS) horsepower, divide by 0.7355 instead.
What if I only know kW? Set PF to 1.00 and enter kW as kVA. The result is kW ÷ 0.7457, adjusted by the efficiency you enter.
Single-phase or three-phase? It only matters when converting volts and amps to kVA. Once you have kVA, the hp formula is the same.
