Enter a power value in kilowatts to see mechanical horsepower (hp) and metric horsepower (PS). For example, 72 kW is approximately 96.5536 mechanical hp or 97.8928 PS. These are two unit descriptions of the same power, not two different performance ratings.
Mechanical horsepower is defined as 550 foot-pounds-force per second. With the international foot and pound and standard gravity, 1 hp equals 745.69987158227022 watts. Metric horsepower is 75 kilogram-force metres per second, so 1 PS equals 735.49875 watts. A PS is a slightly smaller power unit, which is why its numerical result is larger.
Check which horsepower convention your source uses. This converter changes units only: it does not infer shaft output from electrical input, engine output from displacement, or wheel power from a quoted engine rating. Those comparisons require additional measurements or assumptions about losses and test conditions.
The formula
kW- Known power in kilowatts; 1 kW = 1,000 watts.
hp- Mechanical horsepower, defined as 550 ft·lbf/s.
PS- Metric horsepower, defined as 75 kgf·m/s.
Standard gravity- 9.80665 m/s², used in the force-unit definitions. This is a conventional value, not a local gravity measurement.
How to use this calculator
- Enter the power value in kW. A value prefilled by an older conversion link is also interpreted in kW.
- Read the main mechanical-horsepower result and the metric-PS result below it. Select the convention stated by your source.
- To check the arithmetic, multiply kW by 1,000 and divide the watts by 745.69987158227022 for hp or 735.49875 for PS.
- Round the final result to a precision suitable for the original power value. Copy result includes both conventions and the calculation.
Worked examples
42 kW to hp and PS
42 kW = 42,000 W. Dividing by 745.69987158227022 gives approximately 56.32292776 mechanical hp. Dividing by 735.49875 gives approximately 57.10410793 PS. To two decimal places: 56.32 hp or 57.10 PS.
61 kW to horsepower
61,000 W ÷ 745.69987158227022 ≈ 81.80234747 hp. In metric horsepower, 61,000 W ÷ 735.49875 ≈ 82.93691866 PS. Both describe the original 61 kW.
72 kW to horsepower
72,000 W ÷ 745.69987158227022 ≈ 96.55359045 hp. The metric result is 72,000 W ÷ 735.49875 ≈ 97.89275645 PS. Rounded to two decimal places, these are 96.55 hp and 97.89 PS.
Frequently asked questions
How do I convert kW to hp?
For mechanical horsepower, multiply kW by 1,000 and divide by 745.69987158227022. This is approximately kW × 1.341022089595. For metric horsepower (PS), divide the watts by 735.49875 instead, approximately kW × 1.359621617304.
How much horsepower is 72 kW?
72 kW is approximately 96.55359045 mechanical hp or 97.89275645 metric PS. The original power is the same; the unit definitions differ.
What is the difference between hp and PS?
Here hp means mechanical horsepower: 550 foot-pounds-force per second, or 745.69987158227022 W. PS means metric horsepower: 75 kilogram-force metres per second, or 735.49875 W. One mechanical hp is approximately 1.013869665 PS. Check the convention in your source rather than assuming every horsepower label means the same unit.
Does kW to hp account for motor efficiency?
No. Converting a stated electrical input of 10 kW to hp still describes the input power. It does not establish shaft output. Output requires the applicable efficiency or a measurement; the same distinction applies to engine and wheel power.
Are electrical horsepower and boiler horsepower included?
No. They are other conventions. This page compares mechanical horsepower and metric horsepower only. Match the unit definition to the equipment documentation or measurement source.
Why are there more digits than my original power rating?
The arithmetic displays at most 10 significant digits, or 8 in scientific notation for very small or large values. Exact unit definitions do not improve the precision of a measured or rounded rating. Signed inputs are retained as arithmetic values, with a supported range from −10¹⁵ through 10¹⁵ kW.
Kilowatts, mechanical hp and metric PS
| kW | Mechanical hp | Metric PS |
|---|---|---|
| 1 | 1.34102209 | 1.359621617 |
| 42 | 56.32292776 | 57.10410793 |
| 61 | 81.80234747 | 82.93691866 |
| 72 | 96.55359045 | 97.89275645 |
| 100 | 134.102209 | 135.9621617 |