kW to hp Converter
Enter power in kilowatts, choose the horsepower standard, and calculate instantly.
kW to hp conversion formula
Converting kilowatts to horsepower is common when comparing electric motors, pumps, compressors, and engines. The key is knowing which horsepower standard you need. The most frequently used conversion is mechanical horsepower in the US.
- Mechanical horsepower: hp = kW × 1.34102209
- Metric horsepower (PS): PS = kW × 1.35962162
- Electrical horsepower: ehp = kW × 1.34048257
What is the difference between kW and hp?
kW (kilowatt) is a standard SI unit of power used globally in engineering and electrical systems. Horsepower (hp) is an older unit still used in many industries, especially for engines and motor nameplates.
Because horsepower has multiple definitions, two people can convert the same kW number and get slightly different results. For accurate motor power conversion, always confirm whether the requirement calls for mechanical hp, metric hp, or electrical hp.
Step-by-step example
Example: Convert 15 kW to mechanical horsepower
Use the mechanical factor:
hp = 15 × 1.34102209 = 20.11533135
Rounded to two decimals, that is 20.12 hp.
Example: Convert 15 kW to metric horsepower
PS = 15 × 1.35962162 = 20.3943243
Rounded result: 20.39 PS.
Quick kW to hp conversion chart
| kW | Mechanical hp | Metric hp (PS) | Electrical hp |
|---|---|---|---|
| 1 | 1.34 | 1.36 | 1.34 |
| 2.2 | 2.95 | 2.99 | 2.95 |
| 5.5 | 7.38 | 7.48 | 7.37 |
| 7.5 | 10.06 | 10.20 | 10.05 |
| 11 | 14.75 | 14.96 | 14.75 |
| 15 | 20.12 | 20.39 | 20.11 |
| 22 | 29.50 | 29.91 | 29.49 |
| 30 | 40.23 | 40.79 | 40.21 |
| 45 | 60.35 | 61.18 | 60.32 |
| 75 | 100.58 | 101.97 | 100.54 |
When to use each horsepower standard
- Mechanical horsepower: Typical in the US for mechanical output ratings and many industrial datasheets.
- Metric horsepower (PS/cv): Common in Europe and automotive literature.
- Electrical horsepower: Used in electrical engineering contexts and some equipment specifications.
Common mistakes in kW to hp calculation
1) Mixing input and output power
Motor nameplate kW is usually output shaft power. If you compare this to electrical input power without accounting for efficiency, the numbers will not match.
2) Ignoring efficiency
If you are sizing electrical supply, use input power and include motor efficiency. If you are sizing mechanical load, use output power.
3) Rounding too early
For engineering calculations, keep at least 4–6 decimals during intermediate steps and round only at the final stage.
Related calculations you may need
- hp to kW conversion for reverse checks
- Current from kW using voltage and power factor
- Three-phase motor sizing formulas
- Torque from power and RPM
Frequently asked questions
Is 1 kW equal to 1.34 hp exactly?
It is approximately 1.34 hp for mechanical horsepower. The exact factor is 1.34102209.
Why are my online calculator results slightly different?
Different calculators may use different horsepower standards or rounding rules. Small differences are normal.
Can I use this for motor nameplate conversion?
Yes. This calculator is suitable for quick motor power conversion. Just select the horsepower standard required by your project.