Kilowatts are the international unit for engine and motor power: European car registrations, EV spec sheets, generator nameplates and industrial motors all use kW. Horsepower is still what many buyers picture, especially in the US. This converter turns kilowatts into mechanical horsepower and also shows metric horsepower (PS), electrical horsepower and BTU per hour for heating and cooling comparisons.
How to use the kW to hp converter
- Enter the power in Kilowatts (kW).
- Read the result in mechanical horsepower, the unit used in US specifications.
- Check the rows below for metric horsepower (PS), electrical horsepower and BTU per hour.
- Use the motor table to match a metric motor rating to its usual NEMA horsepower size.
kW to horsepower formula
One mechanical horsepower is 745.69987 watts, so one kilowatt is 1,000 ÷ 745.69987 = 1.34102 hp. One metric horsepower (75 kilogram-force meters per second) is 735.49875 W, so one kilowatt is 1.35962 PS. For a quick estimate, add a third to the kW figure: the result is about 0.6% low.
Worked example
An electric SUV lists a combined motor output of 150 kW.
Mechanical hp: 150 × 1.34102209 = 201.2 hp.
Metric hp: 150 × 1.35962 = 203.9 PS.
Quick estimate: 150 + 150/3 = 200 hp.
Another case, a home standby generator rated at 22 kW: 22 × 1.341 = 29.5 hp of electrical output. The engine driving it must make more than that, because the alternator itself loses some power.
Motor sizes: kW and hp
Metric motors follow IEC rating steps, while North American motors follow NEMA horsepower steps. Equipment sold in both markets is matched to the nearest size:
| Metric rating | Exact hp | Usual NEMA size |
|---|---|---|
| 0.75 kW | 1.01 | 1 hp |
| 1.5 kW | 2.01 | 2 hp |
| 3.7 kW | 4.96 | 5 hp |
| 7.5 kW | 10.06 | 10 hp |
| 15 kW | 20.12 | 20 hp |
| 37 kW | 49.62 | 50 hp |
| 75 kW | 100.58 | 100 hp |
kW for heating, cooling and EVs
- Heating and air conditioning. 1 kW of heat is 3,412 BTU per hour. A 3.5 kW mini-split delivers about 11,900 BTU/h, close to a “12,000 BTU” (one-ton) unit.
- EV charging. Charger power is also in kW. A 7.2 kW home charger adds 7.2 kWh per hour of charging, before losses.
- Peak vs. continuous. EV and power-tool makers often quote peak output, which a motor can hold only briefly. Continuous ratings are lower.
Which horsepower to quote?
If you are comparing a European spec (kW and PS) with a US one (hp), convert the kW figure to mechanical hp rather than using the PS number, which is 1.4% higher. Electrical horsepower (746 W) is so close to mechanical horsepower that the difference is under 0.05%.
To convert in the other direction, use hp to kW. For other units such as BTU/h, ft·lbf/s and tons of refrigeration, open the power converter, and to work out power from force, energy or time, try the power calculator.
Frequently asked questions
How many horsepower is 1 kW?
1 kW is 1.341 mechanical horsepower (1.34102209). In metric horsepower it is 1.360 PS, and in electrical horsepower it is 1.340 hp.
What is 100 kW in horsepower?
134.1 hp. In metric horsepower, which European brochures often print next to the kW figure, it is 136 PS.
How do I convert an electric motor's kW rating to hp?
Multiply by 1.341. A 7.5 kW motor is 10.06 hp, which is why it is sold as the metric counterpart of a 10 hp NEMA motor. Motor ratings are output power at the shaft.
Is kW the same as kWh?
No. A kilowatt is a rate of power; a kilowatt-hour is energy, the power used over time. A 150 kW motor running at full output for 2 hours delivers 300 kWh.