Kilowatts to Horsepower Converter

How kilowatts convert to horsepower

Kilowatts (kW) are the SI unit most countries use to rate electric motors, generators, and car engines, while horsepower (hp) is still the headline figure in the United States and for many engine and tool labels. Both measure power, the rate at which work is done, so converting between them is a single multiplication. This calculator uses the mechanical (imperial) horsepower, where one kilowatt equals 1.34102 hp. Use it to compare a 75 kW electric motor with a 100 hp petrol engine, check a pump or compressor nameplate, or translate the power figures in a vehicle spec sheet.

Required Inputs & Typical Use Cases

• Kilowatts

  The power in kW. Decimals such as 5.5 are fine, and commas like 1,250 are accepted.

Typical uses include comparing electric vehicles with petrol or diesel cars, sizing pumps, compressors, and workshop motors, reading imported machinery nameplates, checking generator and outboard ratings, and answering physics or engineering homework that mixes SI and US customary units. For quick planning, remember that 100 kW is about 134 hp and 10 hp is about 7.5 kW.

The Formula

hp = kW × 1.34102
kW = hp ÷ 1.34102   (or hp × 0.7457)

• kW

  Power in kilowatts, where 1 kW = 1,000 watts.

• hp

  Mechanical horsepower, defined as 745.7 watts.

• 1.34102

  Horsepower per kilowatt (1,000 ÷ 745.7).

Worked Example

1. Example 1: 10 kW to horsepower

   10 × 1.34102 = 13.4102 hp.

2. Example 2: a 75 kW electric motor

   75 × 1.34102 = 100.5765 hp, so a 75 kW motor is roughly a 100 hp motor.

3. Example 3: horsepower back to kilowatts

   A 200 hp engine is 200 ÷ 1.34102 ≈ 149.14 kW, or 200 × 0.7457 ≈ 149.14 kW.

Tips, Assumptions & Limitations

• Common mistake: mixing up mechanical horsepower with metric horsepower (PS or CV). One kilowatt is 1.34102 mechanical hp but 1.35962 metric hp, a difference of about 1.4%. Check which one a European spec sheet quotes.
• Common mistake: dividing instead of multiplying. Horsepower numbers are larger than kilowatt numbers, so kW to hp multiplies by about 1.34 and the answer should be bigger.
• Common mistake: confusing power with energy. Kilowatts measure power, while kilowatt-hours measure energy. A battery rated in kWh cannot be converted to hp without knowing the time.
• Common mistake: rounding the factor to 1.3. That undershoots by about 3%, which is roughly 3 hp on a 100 hp engine.
• Engine ratings are often measured at the crank, while wheel horsepower is lower because of drivetrain losses. The conversion itself is unaffected.
• Boiler horsepower and electrical horsepower (746 W) are separate definitions and are not covered by this tool.