What is kilowatt?

A kilowatt is a unit of power equal to 1,000 watts. It is commonly used to rate electric motors, heating systems, solar panels, EV chargers, and industrial equipment.

Real-world uses

Kilowatts are used for rating home electrical systems, electric vehicle charging speeds (Level 2 chargers: 7–22 kW), solar panel array output, electric motors in appliances, and small generators. A typical household may have a peak demand of 3–10 kW.

History

As electricity supply systems expanded in the late 19th century, the kilowatt became the practical unit for measuring power demands and generation capacities beyond the range of single watts. Its adoption enabled standardised rating of motors, generators, and electrical infrastructure.

Common mistakes

Confusing kilowatts (kW, power) with kilowatt-hours (kWh, energy). A 7 kW EV charger running for 2 hours delivers 14 kWh of energy. Also, mixing up kW and kVA in electrical specifications—kVA is apparent power, not real power.

What is horsepower (mechanical)?

Mechanical horsepower is a traditional unit of power equal to approximately 745.7 watts. It is widely used in automotive and industrial contexts to express engine output, pump capacity, and motor ratings.

Real-world uses

Horsepower is used to rate car engines, industrial motors, lawn mowers, outboard boat motors, and air compressors in the United States and some other markets. A typical family car engine ranges from 100–300 hp. It is also used in aviation and marine propulsion ratings.

History

James Watt coined the term "horsepower" around 1782 to help customers understand the power of his steam engines by comparing it to draft horses. He calculated that a horse could perform work at a rate of about 33,000 foot-pounds per minute, which became the definition of one mechanical horsepower.

Common mistakes

There are at least three different definitions: mechanical horsepower (approximately 745.7 W), metric horsepower (735.5 W), and electrical horsepower (746 W). Automotive specifications often do not specify which type is used, and the differences matter when comparing international specifications.

When is this conversion used?

Converting between kilowatt and horsepower (mechanical) is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region.

Worked examples

1 kilowatt = 1.34102209 horsepower (mechanical)

1 horsepower (mechanical) = 745.69987158 watt

How to convert kilowatt to horsepower (mechanical)

To convert kilowatt to horsepower (mechanical), multiply the value by 1.34102209.

To convert horsepower (mechanical) back to kilowatt, multiply by 0.74569987.

Measurement standards

The watt is the SI derived unit of power, defined as one joule per second (kg·m²/s³). Horsepower remains in widespread informal use, particularly in the automotive industry, but has no single universal definition across regions.

Did you know?

The human body at rest produces about 80 watts of power — roughly enough to keep an incandescent light bulb glowing. During intense exercise, a trained cyclist can sustain over 400 watts, and elite sprinters briefly exceed 2,000 watts.

Quick reference: kilowatt to horsepower (mechanical)

kilowatt	horsepower (mechanical)
0.1	0.13410221
0.5	0.67051104
1	1.34102209
2	2.68204418
5	6.70511045
10	13.4102209
25	33.52555224
50	67.05110448
100	134.10220896
250	335.2555224
500	670.5110448
1,000	1,341.0220896

Common values

	kilowatt	horsepower (mechanical)
LED light bulb	0.01 kilowatt	0.01341022 horsepower (mechanical)
Desktop computer	0.3 kilowatt	0.40230663 horsepower (mechanical)
Microwave oven	1 kilowatt	1.34102209 horsepower (mechanical)
Small car engine	75 kilowatt	100.57665672 horsepower (mechanical)
Wind turbine (large)	3,000 kilowatt	4,023.06626879 horsepower (mechanical)

Available Power units

More kilowatt conversions

Assumption: horsepower values use mechanical horsepower.