How this power converter works
Power measures how fast energy is used or produced. It turns up as the kilowatts on an electric motor, the horsepower on a car engine, the BTU per hour on an air conditioner, and the watts on almost every appliance. They all measure the same quantity on different scales. To convert accurately between them, this tool turns whatever you type into a single base unit — the watt — and then expresses that base value in every other unit. Converting through a base avoids the rounding errors that creep in when you chain conversions one after another.
The exact factors used (each expressed in watts) are: 1 kW = 1,000 W, 1 MW = 1,000,000 W, 1 mechanical hp = 745.699872 W, 1 metric hp (PS) = 735.49875 W, 1 BTU/h = 0.29307107 W, and 1 ft·lb/s = 1.35581795 W. The most-searched pairings — horsepower to kilowatts and watts to BTU per hour — are highlighted at the top so you can read them at a glance.
Common conversions
| From | Equals |
|---|---|
| 1 mechanical horsepower (hp) | 745.7 watts (≈ 0.7457 kW) |
| 1 metric horsepower (PS) | 735.5 watts (≈ 0.7355 kW) |
| 1 kilowatt (kW) | 1.341 hp (≈ 1.3596 PS) |
| 1 kilowatt (kW) | 3,412.14 BTU per hour (BTU/h) |
| 1 BTU per hour (BTU/h) | 0.29307 watts |
Reference note: mechanical horsepower (imperial hp) is 745.699872 W and metric horsepower (PS, also CV or pk) is 735.49875 W — they are not interchangeable. Results are rounded for readability.
Frequently asked questions
- How do I convert hp to kW?
- Multiply mechanical horsepower by 0.7457 to get kilowatts, because one mechanical horsepower is 745.699872 watts. For example, 150 hp × 0.7457 ≈ 111.85 kW. This converter shows the result instantly the moment you type a value.
- What is a watt?
- A watt (W) is the SI unit of power, equal to one joule of energy transferred per second. It is the base unit this tool converts through. A kilowatt (kW) is 1,000 watts and a megawatt (MW) is 1,000,000 watts.
- What is the difference between mechanical and metric horsepower?
- Mechanical horsepower (the imperial hp used in the US and UK) equals 745.699872 watts, while metric horsepower (PS, also written CV or pk) equals 735.49875 watts. Metric horsepower is about 1.4 percent smaller, so the same engine rates slightly higher in PS than in hp.
- How many watts are in a horsepower?
- One mechanical horsepower equals 745.699872 watts, often rounded to 745.7 W or 0.7457 kW. One metric horsepower (PS) equals 735.49875 watts, or about 0.7355 kW. So a single horsepower is roughly three-quarters of a kilowatt.
- What is BTU per hour?
- BTU per hour (BTU/h) is a rate of power used mainly for heating and air-conditioning. One BTU/h equals about 0.29307107 watts, so a 12,000 BTU/h air conditioner is roughly 3,517 watts, or 3.52 kW, of thermal power.
- How do I convert kW to hp?
- Divide kilowatts by 0.7457 to get mechanical horsepower, or multiply by about 1.341. For example, 100 kW ÷ 0.7457 ≈ 134.1 hp. For metric horsepower (PS) divide by 0.73550 instead, giving about 1.3596 PS per kilowatt.