Foot-pounds Per Second to Watts (ft⋅lbf/s to W)

1 foot-pound per second equals 1.355817948 watts (rounded).

1 foot-pound per second = 1.355817948 watts

How to convert foot-pounds per second to watts

To convert foot-pounds per second to watts, multiply the number of foot-pounds per second by 1.355817948. The factor is rounded to 10 significant digits. To go the other way, multiply watts by 0.7375621493 (rounded).

watts = foot-pounds per second × 1.355817948

Example: 10 foot-pounds per second = 13.55817948 watts.

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

Foot-pound Per Second (ft⋅lbf/s)

US & ImperialCurrent unit

About 1.3558 watts. A horsepower is 550 of these.

Engineers in the English-speaking world measured work as force times distance, so a pound-force lifted through a foot became a foot-pound, and doing it each second gave the foot-pound per second. It is the base from which horsepower is built, since the imperial horsepower is defined as 550 foot-pounds per second, or 33,000 per minute, the figure fixed by James Watt and Matthew Boulton in 1783.

In SI terms one foot-pound per second is about 1.3558 watts, and NIST lists 1.355818 watts without marking it exact. The reverse is 1 watt equal to 0.7375621 foot-pounds per second. Multiplying 550 by 1.3558 gives about 745.7 watts, the usual value for a mechanical horsepower. The unit is rarely quoted on its own today, though it appears in older mechanics texts and in small-scale power estimates.

1 foot-pound per second = 1.355817948 watts (approximately).

Sources: Wikipedia: Horsepower; Wikipedia: Watt; NIST SP 811, Appendix B.8

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)

Related conversions

See all power units.