Watt to Horsepower Converter

A watt (W) is the SI unit of power, defined as one joule per second. Named after Scottish inventor James Watt, it represents the rate of energy transfer and is fundamental to all power measurements in the International System of Units.

The watt was named after James Watt in 1882 and became the SI unit of power in 1960. It replaced various earlier power units and provided a unified measure based on the fundamental relationship between energy and time, becoming universal in scientific and technical applications.

Watts are universally used for all power measurements, from small electronic devices to large machinery. They're fundamental in electrical engineering, physics, energy efficiency ratings, and form the basis for all other power unit measurements.

Horsepower (hp) is a unit of power originally defined as the power needed to lift 550 pounds one foot in one second, approximately equal to 746 watts. It was created to compare the output of steam engines with the power of draft horses.

Horsepower was defined by James Watt around 1782 to market his steam engines by comparing their output to the familiar power of horses. It became the standard unit for mechanical power in English-speaking countries and remains widely used despite the adoption of SI units.

Horsepower is extensively used in automotive engines, mechanical equipment, and motor specifications. It's standard for car engine ratings, industrial machinery, pumps, and mechanical power transmission systems, particularly in the United States.