Convert Mechanical Horsepower to Kilowatt (hp → kW)

Converting mechanical horsepower to kilowatts is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in mechanical horsepower

   Start with the number of mechanical horsepower (hp) you want to convert.
2. 2
   Multiply by 0.7457

   The conversion factor from hp to kW is 0.7457. Multiply your value by this number.
3. 3
   Read the result in kilowatts

   The result is your value in kilowatts (kW).

Multiply the value in mechanical horsepower by 0.7457. For the reverse direction, multiply by 1.341022.

• ✓1 hp = 745.7 W = 0.7457 kW.
• ✓US car ads quote hp; European ads quote kW or PS.
• ✓Metric horsepower (PS) differs by ~1.4% — be aware.

• ✗Assuming hp and PS are identical — 1.4% difference.
• ✗Using horsepower for electrical devices — watts more appropriate.
• ✗Confusing horsepower at engine flywheel vs wheel (transmission losses).

What is the Mechanical Horsepower?

Horsepower (hp) equals exactly 745.6998715822702 watts (mechanical horsepower) and is the American and British unit for car engines, motorcycles, motorboats, and traditional mechanical power ratings. James Watt invented the unit in the 1780s to market his steam engines: he calculated that a brewery horse could continuously turn a mill wheel at 33,000 ft·lb per minute, which became 1 horsepower. American cars typically range from 150 hp (economy) to 700 hp (sports cars), pickup trucks 250–500 hp, and large diesel trucks 400–600 hp. Outside the US, the metric horsepower (PS or CV, equal to 735.5 W — about 1.4% smaller than mechanical hp) is sometimes used. Horsepower relates to the watt (1 hp ≈ 745.7 W), the kilowatt (1 hp ≈ 0.746 kW), and the metric horsepower (1 hp ≈ 1.014 PS). Despite SI's preference for the watt, horsepower remains entrenched in automotive marketing.

• US car and motorcycle engine ratings
• Lawn mower and small engine specs
• US pump and compressor ratings

What is the Kilowatt?

The kilowatt equals 1,000 watts and is the standard power rating for European cars, household appliances, and small industrial motors. European car engines are rated in kW (a typical economy car has 70–110 kW, a sports car 200–500 kW), even though horsepower is often quoted alongside for marketing. Major household appliances range from 1–3 kW (electric kettle, microwave) to 5–10 kW (electric oven, central air conditioning). Solar panel arrays for homes are sized in kW (typical residential system: 5–10 kW). Electric motors in industry are commonly rated 1 to 500 kW. The kilowatt relates to the watt (1,000 W = 1 kW), the megawatt (1,000 kW = 1 MW), horsepower (1 kW ≈ 1.341 hp), the BTU per hour (1 kW ≈ 3,412 BTU/h), and the kWh of energy when multiplied by hours.

• Car and motorcycle engine ratings (Europe)
• Home electrical service sizing
• HVAC and heating-pump capacity