Horsepower to Kilowatts (hp to kW)
1 horsepower equals 0.7456998716 kilowatts (rounded).
How to convert horsepower to kilowatts
To convert horsepower to kilowatts, multiply the number of horsepower by 0.7456998716. The factor is rounded to 10 significant digits. To go the other way, multiply kilowatts by 1.34102209 (rounded).
kilowatts = horsepower × 0.7456998716
Example: 10 horsepower = 7.456998716 kilowatts.
Several different horsepower units exist. This site lists mechanical (745.7 W), metric (735.5 W) and electrical (746 W) horsepower separately.
About these units
Horsepower (hp)
The mechanical horsepower: 550 foot-pounds per second, about 745.7 watts. James Watt coined it to compare steam engines with draft horses.
Horsepower was a sales pitch before it was a unit. Late in the 18th century the Scottish engineer James Watt adopted the term to compare the output of steam engines with the draft horses they replaced. His 1782 experiments found that a brewery horse could produce 32,400 foot-pounds-force per minute, and in 1783 he and Matthew Boulton standardized the figure at 33,000 foot-pounds-force per minute. Customers could then be told how many horses an engine would replace.
That figure works out to 550 foot-pounds-force per second, or about 745.7 watts: the power needed to lift 550 pounds by one foot in one second. Several cousins exist, including metric horsepower and electrical horsepower, defined as exactly 746 W. Car ratings added more confusion. Early British taxable horsepower was a formula based on bore and cylinder count, not measured output, and American ratings before 1972 used SAE gross brake horsepower, measured without accessories. In the European Union, horsepower may be used only as a supplementary unit under Directive 80/181/EEC, in force from 1 January 2010.
1 horsepower = 745.6998716 watts (approximately).
Sources: Wikipedia: Horsepower; Wikipedia: Metric horsepower
Kilowatt (kW)
1,000 watts. Used for the power of motors, cars and household appliances.
A kilowatt is simply the watt with the SI prefix kilo, meaning a thousand, attached. The watt was adopted into the SI in 1960 and is small next to machinery, since an incandescent night light uses about 4 W, so the thousand-watt multiple suits engines, electric motors, tools and heaters. For readers used to older units, one kilowatt is roughly 1.34 horsepower.
Small electric heaters with a single element can use about 1 kW, and a domestic electric kettle or microwave oven draws a similar amount. The average household in the United States uses about 1 kW of electric power over time. On a clear midday near the equator, a square meter of Earth's surface receives about 1 kW of sunlight. Do not confuse the kilowatt with the kilowatt-hour on an electricity bill: the first is a rate, the second is the energy used by running one kilowatt for an hour, which equals 3,600,000 watt-seconds.
1 kilowatt = 1,000 watts (exactly).
Sources: Wikipedia: Kilowatt; Wikipedia: Orders of magnitude (power); BIPM: SI prefixes
Related conversions
- Kilowatts to horsepower (reverse)
- Horsepower to watts
- Horsepower to megawatts
- Horsepower to gigawatts
- Horsepower to metric horsepower
- Horsepower to BTU per hour
- Horsepower to milliwatts
- Horsepower to electrical horsepower
- Horsepower to foot-pounds per second
- Horsepower to tons of refrigeration
- Horsepower to kilocalories per hour
- Horsepower to calories per second
- Horsepower to ergs per second
- Watts to kilowatts
- Megawatts to kilowatts
- Gigawatts to kilowatts
- Metric horsepower to kilowatts
- BTU per hour to kilowatts
- Milliwatts to kilowatts
- Electrical horsepower to kilowatts
- Foot-pounds per second to kilowatts
- Tons of refrigeration to kilowatts
- Kilocalories per hour to kilowatts
- Calories per second to kilowatts
- Ergs per second to kilowatts
See all power units.