horsepower (mechanical) (hp)

1 horsepower (mechanical) = 745.69987158 watts

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.

Notes: Mechanical power

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 horsepower (mechanical) and watt 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.

How to convert horsepower (mechanical) to watt

To convert horsepower (mechanical) to watt, multiply the value by 745.69987158.

Conversion formula (from base unit)

x * 745.6998715822702

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: horsepower (mechanical) to watt
horsepower (mechanical)watts
0.174.56998716
0.5372.84993579
1745.69987158
21,491.39974316
53,728.49935791
107,456.99871582
2518,642.49678956
5037,284.99357911
10074,569.98715823
250186,424.96789557
500372,849.93579114
1,000745,699.87158227

Common values

Common values
horsepower (mechanical)watts
LED light bulb0.01341022 horsepower (mechanical)10 watts
Desktop computer0.40230663 horsepower (mechanical)300 watts
Microwave oven1.34102209 horsepower (mechanical)1,000 watts
Small car engine100.57665672 horsepower (mechanical)75,000 watts
Wind turbine (large)4,023.06626879 horsepower (mechanical)3,000,000 watts

Full horsepower (mechanical) conversion table

Full horsepower (mechanical) conversion table
Unit Value Factor
watt1 hp = 745.69987158 W× 745.69987158
kilowatt1 hp = 0.74569987 kW× 0.74569987
megawatt1 hp = 0.0007457 MW× 0.0007457
gigawatt1 hp = 7.456999e-07 GW× 7.456999e-07
milliwatt1 hp = 745,699.87158227 mW× 745,699.87158227
microwatt1 hp = 745,699,871.58227026 µW× 745,699,871.58227026
BTU per hour1 hp = 2,544.43357914 BTU/h× 2,544.43357914
kilocalorie per hour1 hp = 641.186476 kcal/h× 641.186476
ton of refrigeration1 hp = 0.21203613 TR× 0.21203613