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
Power Converter
Convert watts, horsepower, refrigeration tons, BTU per hour, and engineering power units.
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 uses the watt as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Horsepowers to Foot-pounds per second
Horsepower and Foot-pound per second both describe power output, and the conversion is a routine part of comparing an engine or motor's spec sheet across countries that use different power units. 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 |
| 100 hp | 55,000 ft-lb/s |
| 500 hp | 275,000 ft-lb/s |
| 1,000 hp | 550,000 ft-lb/s |
| 5,000 hp | 2,750,000 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 power.
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)