Convert Horsepower to Metric Horsepower
Horsepower to metric horsepower is the conversion you need when a car is rated in the mechanical (imperial) horsepower used on US and UK spec sheets, but you want the metric horsepower — PS or CV — quoted across Europe. One mechanical horsepower is approximately 1.013869665424 metric horsepower, because mechanical horsepower is about 1.4% bigger.
Horsepower (mechanical) to Metric horsepower (PS) conversion table
| Horsepower (mechanical) (hp) | Metric horsepower (PS) (PS) |
|---|---|
| 1 | 1.01387 |
| 2 | 2.027739 |
| 3 | 3.041609 |
| 5 | 5.069348 |
| 10 | 10.138697 |
| 20 | 20.277393 |
| 50 | 50.693483 |
| 100 | 101.386967 |
| 500 | 506.934833 |
| 1,000 | 1,013.869665 |
The formula
To convert mechanical horsepower to metric horsepower, multiply the number of horsepower by 1.013869665424 (about 1.01387):
metric horsepower = horsepower × 1.013869665424
A worked example
Say a US-spec car is rated at 150 horsepower and you want the metric horsepower (PS) a European sheet would show:
150 × 1.013869665424 = 152.08045 PS
So 150 mechanical horsepower is about 152 PS.
Why it's an approximation
The two units measure the same thing but start from different definitions. Mechanical (imperial) horsepower is 550 foot-pounds-force per second — about 745.7 watts — while metric horsepower (PS or CV) is defined in metric terms and comes to about 735.5 watts. Because the mechanical one is roughly 1.4% larger, one mechanical horsepower is about 1.013869665424 metric horsepower. The two definitions don't line up cleanly, so the factor is rounded and the result stays approximate. That small gap is why a US spec sheet and a European one can list slightly different horsepower numbers for the very same engine.
When you'll use it
Comparing a US or UK car's horsepower against the PS or CV figures on a European spec sheet, or making sense of why the same engine shows two slightly different horsepower ratings depending on the market.
Frequently asked questions
What's the difference between horsepower and metric horsepower?
They're two slightly different definitions of the same idea. Mechanical (imperial) horsepower — used on US and UK car engines — is about 745.7 watts. Metric horsepower (PS or CV), used on European spec sheets, is about 735.5 watts. So the mechanical one is about 1.4% larger, which is why one mechanical horsepower is about 1.01387 PS.
Are PS, CV, and metric horsepower the same thing?
Yes. PS (from the German Pferdestärke), CV (from the French and Italian), and 'metric horsepower' all name the same unit — about 735.5 watts. They're just different labels for it on different countries' spec sheets.
Is the horsepower to metric horsepower conversion exact?
No. The two horsepowers are defined from different base units that don't line up cleanly, so 1.013869665424 is a rounded value. About 1.01387 works for everyday use; add decimals for more precision.