This HP to kW calculator converts horsepower into kilowatts and back, covering all three horsepower definitions — mechanical (imperial), metric (PS/cv), and electrical. Whether you are reading a US engine spec, a European PS figure, or an electric motor nameplate, this tool gives the correct kilowatt equivalent.
HP to kW Formula
James Watt defined horsepower to compare his steam engines to draft horses. The modern mechanical horsepower equals exactly 745.6999 watts. Because the kilowatt is the SI unit of power used worldwide for electric motors, EVs, and generators, converting between HP and kW is one of the most common power calculations in both automotive and electrical work.
The Three Types of Horsepower
Not all horsepower is identical, and using the wrong one introduces small but real errors:
- Mechanical horsepower (hp): the US/UK standard. 1 hp = 0.7457 kW. Used for most engine and car specs.
- Metric horsepower (PS, cv, ch, pk): common in Europe and Japan. 1 PS = 0.7355 kW — slightly smaller, which is why a "147 kW" engine is marketed as 200 PS but only about 197 mechanical hp.
- Electrical horsepower: used for electric motors in North America. 1 electrical hp = 0.746 kW exactly.
HP to kW Conversion Table
| Horsepower (hp) | Kilowatts (kW) | Metric PS |
|---|---|---|
| 1 | 0.75 | 1.01 |
| 50 | 37.3 | 50.7 |
| 100 | 74.6 | 101.4 |
| 150 | 111.9 | 152.1 |
| 200 | 149.1 | 202.8 |
| 300 | 223.7 | 304.2 |
| 500 | 372.8 | 506.9 |
Worked Example
Going the other way, an electric motor rated 110 kW converts to 110 ÷ 0.7457 ≈ 147.5 hp. To convert torque-based figures instead, see the torque to kW calculator, or use HP to torque if you need pound-feet.
Conversions use exact published constants. Pick the correct horsepower type (mechanical, metric, or electrical) for your source figure to avoid a 1–2% discrepancy.
If your source figure is specifically brake horsepower rather than generic hp, the bhp to kW converter covers the same arithmetic with the badge-versus-paperwork check that European buyers usually need, and kW to bhp handles the reverse.
Electric vehicles are rated in kilowatts, so once you have the kW figure the kW to km/h calculator estimates what it means for road speed.
All Three Horsepower Types, Side by Side
Most conversion mistakes come from mixing horsepower definitions. Mechanical (imperial) HP = 745.7 W, metric HP (PS/cv) = 735.5 W, and electrical HP = 746 W exactly. The ~1.4% gap between mechanical and metric HP is why a "300 PS" European spec equals only 296 imperial HP:
| HP | kW (mechanical, ×0.7457) | kW (metric PS, ×0.7355) | kW (electrical, ×0.746) |
|---|---|---|---|
| 1 | 0.746 | 0.736 | 0.746 |
| 5 | 3.73 | 3.68 | 3.73 |
| 10 | 7.46 | 7.36 | 7.46 |
| 25 | 18.6 | 18.4 | 18.7 |
| 50 | 37.3 | 36.8 | 37.3 |
| 75 | 55.9 | 55.2 | 56.0 |
| 100 | 74.6 | 73.5 | 74.6 |
| 150 | 111.9 | 110.3 | 111.9 |
| 200 | 149.1 | 147.1 | 149.2 |
| 300 | 223.7 | 220.6 | 223.8 |
| 400 | 298.3 | 294.2 | 298.4 |
| 500 | 372.9 | 367.7 | 373.0 |
| 750 | 559.3 | 551.6 | 559.5 |
| 1000 | 745.7 | 735.5 | 746.0 |
Which one do I have? US/UK car specs and dyno sheets → mechanical HP. European/Japanese/Korean specs quoted as PS, cv, or "hp (metric)" → metric HP. Electric motor nameplates in North America → electrical HP. For the reverse direction see kW to HP, and for shaft power from torque see Nm to kW.
Motor Sizes: 1 to 100 HP
Standard industrial motor ratings. These are the sizes you will find on nameplates and in supplier catalogues.
| HP | kW | PS (metric) |
|---|---|---|
| 0.25 | 0.19 | 0.3 |
| 0.5 | 0.37 | 0.5 |
| 0.75 | 0.56 | 0.8 |
| 1 | 0.75 | 1.0 |
| 1.5 | 1.12 | 1.5 |
| 2 | 1.49 | 2.0 |
| 3 | 2.24 | 3.0 |
| 4 | 2.98 | 4.1 |
| 5 | 3.73 | 5.1 |
| 7.5 | 5.59 | 7.6 |
| 10 | 7.46 | 10.1 |
| 15 | 11.19 | 15.2 |
| 20 | 14.91 | 20.3 |
| 25 | 18.64 | 25.3 |
| 30 | 22.37 | 30.4 |
| 40 | 29.83 | 40.6 |
| 50 | 37.28 | 50.7 |
| 60 | 44.74 | 60.8 |
| 75 | 55.93 | 76.0 |
| 100 | 74.57 | 101.4 |
Car and Engine Outputs: 100 to 1000 HP
The range most vehicle specifications fall into. Note that European brochures usually quote PS rather than mechanical HP — the third column shows the difference, which grows to about 14 units at the 1000 HP end.
| HP | kW | PS (metric) |
|---|---|---|
| 100 | 74.57 | 101.4 |
| 110 | 82.03 | 111.5 |
| 125 | 93.21 | 126.7 |
| 134 | 99.92 | 135.9 |
| 140 | 104.40 | 141.9 |
| 150 | 111.85 | 152.1 |
| 160 | 119.31 | 162.2 |
| 175 | 130.50 | 177.4 |
| 180 | 134.23 | 182.5 |
| 200 | 149.14 | 202.8 |
| 220 | 164.05 | 223.1 |
| 250 | 186.42 | 253.5 |
| 280 | 208.80 | 283.9 |
| 300 | 223.71 | 304.2 |
| 350 | 260.99 | 354.9 |
| 400 | 298.28 | 405.5 |
| 450 | 335.56 | 456.2 |
| 500 | 372.85 | 506.9 |
| 600 | 447.42 | 608.3 |
| 700 | 521.99 | 709.7 |
| 800 | 596.56 | 811.1 |
| 1000 | 745.70 | 1013.9 |
Quick Reference Points Worth Memorising
- 1 HP ≈ 0.75 kW — accurate to within 0.6%, good enough for mental arithmetic.
- 100 HP ≈ 75 kW — the same shortcut scaled up.
- 1 kW ≈ 1.34 HP — the reverse.
- 200 HP = 149 kW — a common car figure worth anchoring on.
For single conversions use our HP to kW calculator or kW to HP. If your source quotes PS, KM or KS rather than mechanical horsepower, the kW to PS converter handles that scale, and the horsepower unit converter covers every unit at once.
The Two Different Steps
Step one is a unit conversion. Horsepower and kilowatts measure the same thing in different units, so 300 WHP is 223.7 kW measured at exactly the same place — the wheels. Multiply by 0.7457 and you are done. Nothing is added or removed.
Step two is a location change. Moving from wheel power to crank power means accounting for what the gearbox, driveshafts and differential absorb. That is an estimate, not a conversion, and it depends on the drivetrain layout.
Keep them separate and the arithmetic stays honest. If someone quotes "300 WHP = 263 kW", they have silently done both steps — which is fine, as long as everyone knows the kW figure is now a crank number being compared against a wheel number.
WHP to kW Conversion Chart
All three columns describe power at the wheels — no drivetrain estimate is involved. PS is metric horsepower, used on most continental European spec sheets.
| WHP | kW at wheels | PS at wheels |
|---|---|---|
| 150 | 111.9 | 152.1 |
| 200 | 149.1 | 202.8 |
| 250 | 186.4 | 253.5 |
| 300 | 223.7 | 304.2 |
| 400 | 298.3 | 405.5 |
| 500 | 372.8 | 506.9 |
| 600 | 447.4 | 608.3 |
| 800 | 596.6 | 811.1 |
For crank horsepower — the figure manufacturers quote — you need the drivetrain step, which is a separate estimate rather than a conversion. Our WHP to HP chart covers that across FWD, RWD and AWD.
Frequently Asked Questions
No, but they both measure power. 1 kW is larger than 1 HP. 1 kW equals roughly 1.34 HP.
Metric horsepower (often written as PS, cv, or ch) is defined as the power required to lift 75 kilograms by 1 meter in 1 second. It equals 735.5 watts, slightly less than mechanical HP.
One mechanical horsepower equals 0.7457 kilowatts. Metric horsepower (PS) is slightly less at 0.7355 kW, and electrical horsepower is 0.746 kW.
kW is the official SI unit required on documents, while PS (metric horsepower) is the traditional figure buyers recognize, so manufacturers print both.
One kilowatt is larger than one horsepower — 1 kW equals about 1.341 HP. So a 100 kW motor is roughly 134 HP.