Horsepower Calculator
Convert between horsepower, watts, and kilowatts instantly with accurate mechanical hp conversions.
How it works
- 1Enter a power value and choose its unit — horsepower (hp), watts (W), or kilowatts (kW).
- 2The calculator converts your input to watts using 1 hp = 745.7 W, then derives all three units.
- 3Results update instantly: horsepower is the headline result; watts and kilowatts appear below.
Use cases
- Compare engine ratings — convert a car’s 300 hp to kilowatts for European specs (≈ 224 kW).
- Size electrical equipment — find how many watts a 5 hp motor draws at full load (≈ 3729 W).
- Understand appliance labels — a 1.5 kW kettle is about 2.01 hp.
Frequently asked questions
How many watts is 1 horsepower?
One mechanical horsepower equals about 745.7 W, so 1 hp ≈ 0.7457 kW. For example, 100 hp = 100 × 745.7 = 74,570 W ≈ 74.57 kW.
How many horsepower is 1 kilowatt?
1 kW ÷ 745.7 ≈ 1.341 hp, so a 100 kW electric motor produces about 134.1 hp. This ratio is handy when comparing European kW ratings with North American hp.
What is the difference between mechanical and metric horsepower?
Mechanical (imperial) horsepower, used in the US, is 745.7 W. Metric horsepower (PS, CV) is 75 kgf·m/s ≈ 735.5 W, about 1.4% less. This calculator uses mechanical horsepower.
Related tools
See all →Calculate average velocity from displacement and time, in metric or imperial units.
Calculate average velocity from displacement and time, or from initial and final speeds.
Calculate average acceleration from initial velocity, final velocity, and elapsed time.
Calculate average acceleration from change in velocity and time interval in metric or imperial units.