How to Convert Horsepower to Kilowatts (and Back)
Horsepower and kilowatts are both units of power — the rate at which energy is produced or consumed. Cars sold in the US and UK are rated in horsepower (hp), while European manufacturers use kilowatts (kW) or metric horsepower (PS). Electric vehicles are increasingly rated in kW. This guide explains both units, the mechanical vs metric horsepower difference, and gives you the exact conversion formula.
What Is Horsepower?
Horsepower (hp) was originally defined by James Watt in the 18th century to compare steam engine output to the power of draft horses. It became the standard for rating engine power in the US and UK.
1 mechanical horsepower (hp) = 745.69987 watts. This is the standard used in the US for car engine ratings.
1 metric horsepower (PS or CV) = 735.49875 watts. PS (from the German "Pferdestärke") is used by most European car manufacturers. The two are very similar but not identical — 100 PS ≈ 98.6 hp.
What Is a Kilowatt?
A kilowatt (kW) equals exactly 1,000 watts. It is the SI-derived unit of power and is used worldwide for electrical systems, industrial motors, and increasingly for car engine ratings.
Electric vehicles are always rated in kW (and sometimes kWh for battery capacity). Many European countries now show both kW and PS in car specifications.
The Conversion Formula
Mechanical hp to kW: multiply by 0.7457. Example: 200 hp × 0.7457 = 149.1 kW.
kW to mechanical hp: multiply by 1.341. Example: 150 kW × 1.341 = 201.2 hp.
Metric hp (PS) to kW: multiply by 0.7355. Example: 200 PS × 0.7355 = 147.1 kW.
kW to PS: multiply by 1.3596. Example: 150 kW × 1.3596 = 203.9 PS.
Car Power Reference Table
Common engine outputs in both units (mechanical hp):
- 100 hp = 74.6 kW (small city car)
- 150 hp = 111.9 kW (typical compact sedan)
- 200 hp = 149.1 kW (performance compact)
- 300 hp = 223.7 kW (sports car)
- 400 hp = 298.3 kW (high-performance)
- 500 hp = 372.9 kW (supercar territory)
- 1,000 hp = 745.7 kW (hypercar)
Electric Vehicle Power
Electric motors produce power measured in kW. A base Tesla Model 3 produces about 283 kW (380 hp). The Porsche Taycan Turbo S produces 560 kW (750 hp) in boost mode.
Unlike combustion engines, electric motors produce maximum torque instantly and can sustain peak power for longer periods, making raw horsepower comparisons with combustion engines somewhat misleading.
Conclusion
1 mechanical hp = 0.7457 kW. 1 kW = 1.341 hp. For metric horsepower (PS): 1 PS = 0.7355 kW. The difference between hp and PS is small (about 1.4%) but matters for precise engineering specifications. Use our free power converter for instant results.