Convert Foot-Pound per Second to Watt (ft·lbf/s → W)

Converting foot-pounds per second to watts is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in foot-pounds per second

   Start with the number of foot-pounds per second (ft·lbf/s) you want to convert.
2. 2
   Multiply by 1.355818

   The conversion factor from ft·lbf/s to W is 1.355818. Multiply your value by this number.
3. 3
   Read the result in watts

   The result is your value in watts (W).

Multiply the value in foot-pounds per second by 1.355818. For the reverse direction, multiply by 0.737562.

• ✓1 ft·lbf/s = 1.356 W.
• ✓550 ft·lbf/s = 1 mechanical hp.
• ✓Rarely needed today outside archival references.

• ✗Confusing ft·lbf/s (power) with ft·lbf (torque or work).
• ✗Using in modern specifications — prefer W or kW.
• ✗Mixing with foot-pound (energy) in same calculation.

What is the Foot-Pound per Second?

The foot-pound per second (ft·lb/s) is the American mechanical-power unit, used in engineering and machine-rating contexts. James Watt's original definition of 1 horsepower was 33,000 ft·lb/min = 550 ft·lb/s, so the foot-pound per second is the granular American power unit underlying horsepower calculations. It is rare in everyday use (kW or hp dominate American power specifications) but appears in engineering thermodynamics textbooks, mechanical-design calculations, and ballistics-energy contexts. The ft·lb/s relates to the watt (1 ft·lb/s ≈ 1.356 W), horsepower (550 ft·lb/s = 1 hp), and the BTU per hour (1 ft·lb/s ≈ 4.626 BTU/h). It is part of the legacy US customary unit system that retains a foothold in mechanical engineering despite metric advancement.

• Older US mechanical-engineering calculations
• Some US physics textbooks
• Classical-mechanics problems

What is the Watt?

The watt is the SI unit of power, equal to one joule per second (1 W = 1 J/s). Named after Scottish engineer James Watt (1736–1819), whose improvements to the steam engine sparked the Industrial Revolution, the watt unifies mechanical, electrical, and thermal power. A typical LED bulb consumes 8–12 W to produce as much light as a 60-W incandescent bulb. Human resting metabolism is about 80–100 W of heat output, while peak athletic performance reaches 400–1,500 W (briefly). The watt is fundamental in electrical engineering: P = V × I (power = voltage × current). It relates to the kilowatt (1 kW = 1,000 W), the megawatt (1 MW = 10⁶ W), horsepower (1 hp ≈ 745.7 W), and the BTU per hour (1 W ≈ 3.412 BTU/h). Light bulb and appliance ratings, electric motor outputs, and audio amplifier specifications all use the watt as the base unit.

• Light-bulb and appliance ratings
• Scientific and engineering power specs
• Radio and electronics power