Electrical Horsepower to Kilowatts (hp (E) to kW)
1 electrical horsepower equals 0.746 kilowatts exactly.
How to convert electrical horsepower to kilowatts
To convert electrical horsepower to kilowatts, multiply the number of electrical horsepower by 0.746. This factor is exact. To go the other way, multiply kilowatts by 1.340482574 (rounded).
kilowatts = electrical horsepower × 0.746
Example: 10 electrical horsepower = 7.46 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
Electrical Horsepower (hp (E))
Exactly 746 watts, the horsepower used for electrical power.
Electrical horsepower exists because electric motors needed a rating that fits neatly with watts. Mechanical horsepower goes back to James Watt, who compared steam engines with brewery horses and, with Matthew Boulton, settled on 33,000 foot-pounds per minute in 1783. That works out to about 745.7 watts. The electrical version rounds the figure to exactly 746 watts, so that motor ratings convert cleanly to kilowatts.
The difference from the mechanical unit is under 0.05 percent, far smaller than the gap to the metric horsepower of about 735.5 watts, which is roughly 98.6 percent of the imperial one. A motor nameplate normally states shaft output, not the electrical power drawn from the supply, and US nameplates use horsepower where most other countries use watts or kilowatts. NIST lists the electric horsepower as exactly 746 watts.
1 electrical horsepower = 746 watts (exactly).
Sources: Wikipedia: Horsepower; NIST SP 811, Appendix B.8
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 electrical horsepower (reverse)
- Electrical horsepower to watts
- Electrical horsepower to horsepower
- Watts to kilowatts
- Horsepower to kilowatts
- Megawatts to kilowatts
- Gigawatts to kilowatts
- Metric horsepower to kilowatts
- BTU per hour to kilowatts
- Milliwatts 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.