Mechanical power rate.
Foot-pounds per second to Horsepowers Converter — ft-lb/s to hp
Convert Foot-pound per second (ft-lb/s) to Horsepower (hp) using the exact conversion factor (1 foot-pound per second = 0.0018181818 horsepower). See the formula, worked examples, conversion table, history, and common uses.
Foot-pounds per second to Horsepowers 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 horsepower.
Result = input x 1.355817948 / 745.6998716.
Power uses the watt as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Foot-pounds per second to Horsepowers
Foot-pound per second and Horsepower 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. Specifically: Mechanical power rate, and mechanical horsepower.
Formula
horsepowers = foot-pounds per second × 0.00181818181818
This factor comes from each unit's defined relationship to the category's base unit: 1 foot-pound per second equals 1.35581794833 base units, and 1 horsepower equals 745.699871582 base units, so dividing one by the other gives the direct foot-pound per second-to-horsepower factor of 0.00181818181818.
Simple example
1 ft-lb/s × 0.001818181818 = 0.0018181818 hp
1 foot-pound per second = 0.0018181818 horsepowers.
Real-world example
100 ft-lb/s × 0.001818181818 = 0.1818181818 hp
100 foot-pounds per second = 0.1818181818 horsepowers.
Conversion table
| Foot-pound per second (ft-lb/s) | Horsepower (hp) |
|---|---|
| 1 ft-lb/s | 0.0018181818 hp |
| 10 ft-lb/s | 0.0181818182 hp |
| 100 ft-lb/s | 0.1818181818 hp |
| 500 ft-lb/s | 0.9090909091 hp |
| 1,000 ft-lb/s | 1.818181818 hp |
| 5,000 ft-lb/s | 9.090909091 hp |
Reverse conversion: Horsepower to Foot-pound per second
0.0018181818 hp × 550 = 0.99999999 ft-lb/s
0.0018181818 horsepowers = 0.99999999 foot-pounds per second.
foot-pounds per second = horsepowers × 550
For a page dedicated to this direction, see Horsepower to Foot-pound per second.
Understanding the Foot-pound per second (ft-lb/s)
Mechanical power rate.
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.
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 horsepowers are in 1 foot-pound per second?
1 foot-pound per second equals 0.0018181818 horsepowers, using the exact defined conversion factor rather than an estimate.
How do I convert foot-pound per second to horsepower?
Multiply the foot-pound per second value by 0.001818181818. The converter above does this instantly to whatever precision you set.
How do I convert horsepower back to foot-pound per second?
Use the reverse factor: 1 horsepower equals 550 foot-pounds per second. You can also use the swap control in the converter above to flip the direction instantly.
What is a foot-pound per second?
Foot-pound per second (ft-lb/s) is a unit of power.
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.
Is the foot-pound per second to horsepower 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.