Watts to Metric Horsepower (W to PS)

1 watt equals 0.001359621617 metric horsepower (rounded).

How to convert watts to metric horsepower

To convert watts to metric horsepower, multiply the number of watts by 0.001359621617. The factor is rounded to 10 significant digits. To go the other way, multiply metric horsepower by 735.49875.

metric horsepower = watts × 0.001359621617

Example: 10 watts = 0.01359621617 metric horsepower.

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

Watt (W)

Metric (SI)Current unit

The SI unit of power: one joule per second. A typical LED bulb uses 5–10 W and a laptop 30–60 W.

Credit for the name goes to C. William Siemens, who proposed it in August 1882 in his presidential address to the British Association for the Advancement of Science. He chose it to honor James Watt, the Scottish inventor who in 1776 improved the Newcomen steam engine. An International Conference on Electric Units and Standards adopted Siemens' definition in London in October 1908 as the international watt. After the 1948 General Conference on Weights and Measures the unit was redefined in absolute terms, and in 1960 the 11th General Conference adopted it into the SI as the unit of power.

Today one watt is one joule per second, or equivalently one volt times one ampere. Orders-of-magnitude tables put an LED light bulb at about 7 W and an adult's basal metabolic rate at roughly 100 W. A 100 kg person climbing a 3 m ladder in 5 seconds works at about 600 W, while a laborer can sustain around 75 W over an eight-hour day. The watt measures a rate, so it says how fast energy is being used, not how much has been used in total.

The watt is the reference unit for power on this site.

Sources: Wikipedia: Watt; Wikipedia: Orders of magnitude (power)

Metric Horsepower (PS)

Metric (SI)Current unit

Exactly 735.49875 watts, the power to lift 75 kilograms by one meter in one second. Called PS, CV or pk and used for car engines in Europe and Asia.

Continental Europe built its own horsepower on kilograms and meters instead of pounds and feet. The metric horsepower, written PS from the German Pferdestarke, is the power needed to lift 75 kilograms by one meter in one second, or 75 kilogram-force meters per second. The German standard DIN 66036 gives its value as 735.49875 W, about 98.6 percent of the imperial horsepower. It goes by many local names, among them cv in Italian and Portuguese, pk in Dutch, ch in French and hk in Swedish, Danish and Norwegian.

It had a French predecessor in the poncelet, a 19th-century unit based on 100 kgf-m/s. In 1972 the European Economic Community replaced PS with the kilowatt as its official unit for power, yet car brochures in many countries still quote PS or its cousins alongside kilowatts. When comparing a European car with an American one, remember that the two horsepowers differ by about 1.4 percent.

1 metric horsepower = 735.49875 watts (exactly).

Sources: Wikipedia: Metric horsepower; Wikipedia: Horsepower

Related conversions

See all power units.