Convert Mechanical Horsepower to Foot-Pound per Second (hp → ft·lbf/s)
Horsepower is the American and British unit for car engines, motorcycles, and traditional mechanical power ratings.
Mechanical Horsepower to Foot-Pound per Second Conversion Table
10 common values| Mechanical Horsepower | Foot-Pound per Second |
|---|---|
| 1 hp | 550 ft·lbf/s |
| 5 hp | 2,750 ft·lbf/s |
| 10 hp | 5,500 ft·lbf/s |
| 50 hp | 27,500 ft·lbf/s |
| 100 hp | 55,000 ft·lbf/s |
| 500 hp | 275,000 ft·lbf/s |
| 1,000 hp | 550,000 ft·lbf/s |
| 5,000 hp | 2,750,000 ft·lbf/s |
| 10,000 hp | 5,500,000 ft·lbf/s |
| 50,000 hp | 27,500,000 ft·lbf/s |
How to Convert Mechanical Horsepower to Foot-Pound per Second Manually
Step by StepConverting mechanical horsepower to foot-pounds per second is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.
- 1Take your value in mechanical horsepowerStart with the number of mechanical horsepower (hp) you want to convert.
- 2Multiply by 550The conversion factor from hp to ft·lbf/s is 550. Multiply your value by this number.
- 3Read the result in foot-pounds per secondThe result is your value in foot-pounds per second (ft·lbf/s).
Formula
Multiply the value in mechanical horsepower by 550. For the reverse direction, multiply by 0.001818.
ft·lbf/s = hp × 550hp = ft·lbf/s × 0.001818Tips
Use these in everyday conversions- 1 hp = 745.7 W = 0.7457 kW.
- US car ads quote hp; European ads quote kW or PS.
- Metric horsepower (PS) differs by ~1.4% — be aware.
Common Mistakes
Avoid these- Assuming hp and PS are identical — 1.4% difference.
- Using horsepower for electrical devices — watts more appropriate.
- Confusing horsepower at engine flywheel vs wheel (transmission losses).
About Mechanical Horsepower and Foot-Pound per Second
What is the Mechanical Horsepower?
Horsepower (hp) equals exactly 745.6998715822702 watts (mechanical horsepower) and is the American and British unit for car engines, motorcycles, motorboats, and traditional mechanical power ratings. James Watt invented the unit in the 1780s to market his steam engines: he calculated that a brewery horse could continuously turn a mill wheel at 33,000 ft·lb per minute, which became 1 horsepower. American cars typically range from 150 hp (economy) to 700 hp (sports cars), pickup trucks 250–500 hp, and large diesel trucks 400–600 hp. Outside the US, the metric horsepower (PS or CV, equal to 735.5 W — about 1.4% smaller than mechanical hp) is sometimes used. Horsepower relates to the watt (1 hp ≈ 745.7 W), the kilowatt (1 hp ≈ 0.746 kW), and the metric horsepower (1 hp ≈ 1.014 PS). Despite SI's preference for the watt, horsepower remains entrenched in automotive marketing.
- US car and motorcycle engine ratings
- Lawn mower and small engine specs
- US pump and compressor ratings
Base Ford Mustang: ~310 hp. Lawn mower: 5 hp. Average car: 150–200 hp.
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
Largely historical; modern specs use W or hp.