Convert horsepower and kilowatts
Type into either field. One mechanical horsepower is 0.7457 kW exactly. Metric horsepower (PS) is shown alongside, because it is a third figure that gets confused with both.
| Typical power | hp | kW | PS | Where you see it |
|---|---|---|---|---|
| 100 hp | 100 | 75 | 101 | Small economy car |
| 200 hp | 200 | 149 | 203 | Midsize sedan, upper trim |
| 300 hp | 300 | 224 | 304 | Sports sedan / performance V6 |
| 450 hp | 450 | 336 | 456 | Muscle car, modern V8 |
| 700 hp | 700 | 522 | 710 | Supercar territory |
| 1000 hp | 1000 | 746 | 1014 | Hypercar / top-tier EV |
Need torque and RPM too? The horsepower, torque and RPM calculator solves for any one of the three from the other two.
Getting a number you can act on
- 01Type into whichever field matches your source
The other field converts immediately. PS is shown alongside both as a reference, since it is a third figure people frequently confuse with kW.
- 02Don't assume kW and PS are the same number
They are close but not identical — PS is about 36% larger than kW numerically, while hp and PS differ by only about 1.4%. Mixing up kW and PS produces a much bigger error than mixing up hp and PS.
- 03Check whether a figure is crank or wheel power
This converter changes units, not measurement point. A dyno figure measured at the wheels is already lower than the equivalent crank figure due to drivetrain loss, in any unit.
- 04Use the reference table as a sanity check
If a converted figure looks far outside where the vehicle class normally sits, that is worth a second look before trusting the source number.
What the calculator is actually doing
Nothing here is proprietary. If you would rather check it by hand, or explain it to someone at a counter, these are the same expressions the tool evaluates.
kW = hp × 0.7457One mechanical horsepower is exactly 745.7 watts.
hp = kW ÷ 0.7457The same relationship reversed.
PS = hp × 1.01387Metric horsepower is defined slightly differently and comes out about 1.4% larger for the same engine.
Why three units still describe the same thing
Mechanical horsepower was defined in the 18th century as a practical comparison to draft-horse output, and it stuck as the standard unit across markets that inherited British and American engineering convention.
Kilowatts are the SI power unit, and every current global manufacturer specification uses them somewhere in the documentation, because SI units are what international standards and most engineering work are built around.
Metric horsepower — PS, from the German Pferdestärke — is an older continental European definition that predates SI adoption and still appears in Japanese and some European market materials out of convention. It is close to mechanical horsepower but not identical, being defined against 75 kgf·m/s rather than 33,000 ft·lb/min, which is why the two numbers differ by about 1.4% rather than being the same figure under two names.
HP to kW Converter FAQ
How do I convert hp to kW?+
Multiply by 0.7457. So 300 hp is about 223.7 kW.
How do I convert kW to hp?+
Divide by 0.7457. So 200 kW is about 268.2 hp.
Is PS the same as hp?+
Very close but not identical — PS is about 1.4% larger for the same engine, since it is defined against a slightly different reference than mechanical horsepower.
Is PS the same as kW?+
No, and this is the pairing worth being careful with — PS is about 36% larger numerically than kW for the same engine, a much bigger gap than the hp/PS difference.
What is 150 kW in horsepower?+
About 201.2 hp — a common power output for a midsize performance sedan.
Standards and references behind these figures
The arithmetic on this page is fixed, but the boundaries and conventions around it come from published standards and manufacturer guidance. These are the documents they come from, so you can check them rather than take them on trust.
01Dyno correction factors — SAE J1349 against STDExplains the J1349 reference conditions of 77°F, 0% humidity and 29.234 in-Hg, and why STD-corrected figures read higher.↗02Ford Performance — dynamometer testing and engine performance tech tipsManufacturer guidance on dyno correction and how quoted power figures are arrived at.↗Convert, then check the tolerance. A converted figure is exact, but the specification it came from was not. Torque specs carry a tolerance and pressure figures are stated cold, so rounding to a value your tool can actually set is normally fine — provided you know which way you rounded and by how much.