Mechanical horsepower.
Horsepowers to Foot-pounds per second Converter — hp to ft-lb/s
Convert Horsepower (hp) to Foot-pound per second (ft-lb/s) using the exact conversion factor (1 horsepower = 550 foot-pound per second). See the formula, worked examples, conversion table, history, and common uses.
Horsepowers to Foot-pounds per second converter
Converter
Engineering Converter
Convert common stress, force, torque, power, and energy units used in engineering.
Context values
Some unit families need one extra value for a physically accurate result.
Mechanical power rate.
Result = input x 745.6998716 / 1.355817948.
Power units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Horsepowers to Foot-pounds per second
Horsepower and Foot-pound per second both measure a quantity used in structural or mechanical engineering — commonly stress, pressure, force, torque, power, or energy — where converting between the unit conventions used in different regions, industries, or equipment specifications is a routine part of design work. Horsepower is most often used for us and uk vehicle engine power ratings.
Formula
foot-pounds per second = horsepowers × 550
This factor comes from each unit's defined relationship to the category's base unit: 1 horsepower equals 745.699871582 base units, and 1 foot-pound per second equals 1.35581794833 base units, so dividing one by the other gives the direct horsepower-to-foot-pound per second factor of 550.
Simple example
1 hp × 550 = 550 ft-lb/s
1 horsepower = 550 foot-pounds per second.
Real-world example
100 hp × 550 = 55,000 ft-lb/s
100 horsepowers = 55,000 foot-pounds per second.
Conversion table
| Horsepower (hp) | Foot-pound per second (ft-lb/s) |
|---|---|
| 1 hp | 550 ft-lb/s |
| 10 hp | 5,500 ft-lb/s |
| 50 hp | 27,500 ft-lb/s |
| 100 hp | 55,000 ft-lb/s |
| 500 hp | 275,000 ft-lb/s |
| 1,000 hp | 550,000 ft-lb/s |
Reverse conversion: Foot-pound per second to Horsepower
550 ft-lb/s × 0.001818181818 = 1 hp
550 foot-pounds per second = 1 horsepowers.
horsepowers = foot-pounds per second × 0.00181818181818
For a page dedicated to this direction, see Foot-pound per second to Horsepower.
Understanding the Horsepower
Horsepower (hp) measures power. Mechanical horsepower is defined as exactly 745.6998715822702 watts. It is classified as a US/imperial customary unit.
Where it's used: United States and United Kingdom (vehicle and engine specifications)
Mechanical horsepower vs. metric horsepower. Mechanical horsepower (745.7 W) and metric horsepower/PS (735.5 W) differ by about 1.4% — a US car spec sheet in 'hp' and a European one in 'PS' are not directly comparable numbers without conversion.
Uses of the Horsepower today
- US and UK vehicle engine power ratings
- Motor and engine specifications in English-speaking markets
History of the Horsepower
James Watt popularized horsepower in the 1780s as a marketing figure, comparing his steam engines' output to the working capacity of a horse (based on his estimate of a horse turning a mill), so buyers could grasp engine capability in familiar terms. The unit stuck long after its origin as a sales tool, eventually being formally defined at exactly 550 foot-pounds per second.
Historical origin. Horsepower was not the invention of a single named person; it developed through the process described above.
Understanding the Foot-pound per second (ft-lb/s)
Mechanical power rate.
Horsepower — sources
- NIST Special Publication 811 — Documents the exact watt-equivalence of mechanical horsepower.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many foot-pounds per second are in 1 horsepower?
1 horsepower equals 550 foot-pounds per second, using the exact defined conversion factor rather than an estimate.
How do I convert horsepower to foot-pound per second?
Multiply the horsepower value by 550. The converter above does this instantly to whatever precision you set.
How do I convert foot-pound per second back to horsepower?
Use the reverse factor: 1 foot-pound per second equals 0.0018181818 horsepowers. You can also use the swap control in the converter above to flip the direction instantly.
What is a horsepower?
Horsepower (hp) measures power. Mechanical horsepower is defined as exactly 745.6998715822702 watts. It is classified as a US/imperial customary unit.
What is a foot-pound per second?
Foot-pound per second (ft-lb/s) is a unit of engineering.
Is the horsepower to foot-pound per second conversion exact?
Yes. Mechanical horsepower is defined as exactly 745.6998715822702 watts. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between mechanical horsepower vs. metric horsepower?
Mechanical horsepower (745.7 W) and metric horsepower/PS (735.5 W) differ by about 1.4% — a US car spec sheet in 'hp' and a European one in 'PS' are not directly comparable numbers without conversion.
Where is the horsepower still used today?
United States and United Kingdom (vehicle and engine specifications)