Horsepower (Metric) to Foot pounds-force second
hp
ft·lbf/s
Conversion History
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Quick Reference Table (Horsepower (Metric) to Foot pounds-force second)
| Horsepower (Metric) (hp) | Foot pounds-force second (ft·lbf/s) |
|---|---|
| 0.5 | 271.2380194196349172779 |
| 1 | 542.47603883926983455579 |
| 10 | 5,424.76038839269834555795 |
| 100 | 54,247.6038839269834555795 |
| 200 | 108,495.207767853966911159 |
| 500 | 271,238.0194196349172778975 |
| 1,000 | 542,476.038839269834555795 |
About Horsepower (Metric) (hp)
Metric horsepower (PS or CV, from German Pferdestärke or French Cheval-vapeur) equals exactly 75 kgf·m/s or 735.49875 watts. It is the standard for automotive engine power ratings in continental Europe, Japan, and many other countries. A typical family car engine produces 70–150 PS; sports cars 200–500 PS; hypercars exceeding 1,000 PS. The metric hp is about 1.4% less than the mechanical (British) horsepower (745.7 W).
A VW Golf 1.5 TSI produces about 130 PS (96 kW). A Porsche 911 Turbo S produces 650 PS (478 kW). The metric hp is the number on European car spec sheets.
Etymology: Introduced in the late 19th century as a metric alternative to Watt's mechanical horsepower, defined as the power to raise 75 kilograms by one meter per second. Widely adopted in continental Europe and Japan; standardized as the PS (Pferdestärke) in Germany.
About Foot pounds-force second (ft·lbf/s)
Foot pounds-force per second (ft·lbf/s) is the fundamental mechanical power unit in the US customary system, equal to approximately 1.356 watts. It is the rate of doing work when a force of one pound-force moves through one foot per second. The unit is directly related to the mechanical horsepower: one horsepower equals exactly 550 ft·lbf/s. It appears in US mechanical engineering, ballistics, and machinery design texts.
One mechanical horsepower equals 550 ft·lbf/s (~746 W). A person climbing stairs moderately expends about 200–300 ft·lbf/s of mechanical power.
Horsepower (Metric) – Frequently Asked Questions
Why do European cars list PS instead of hp?
EU regulations require engine power in kilowatts, but consumers prefer a familiar number. Continental Europe adopted metric horsepower (PS) in the 19th century, and car culture cemented it. Germans say "PS," French say "CV," Italians say "CV" too. The UK uses "bhp" (British horsepower). A 200 PS car is 197 hp — close enough that most people don't notice the 1.4% difference. Japanese manufacturers use PS as well (sometimes written 馬力).
How does a car with 100 PS actually feel to drive?
In a light car (1,000 kg), 100 PS gives a power-to-weight ratio of 100 PS/tonne — adequate for city driving with 0–100 km/h in about 10–11 seconds. In a heavy SUV (2,000 kg), 100 PS feels sluggish, struggling on hills and taking 15+ seconds to reach highway speed. The magic number for "fun" is roughly 150–200 PS per tonne — which is why a 90 PS Mazda MX-5 (1,000 kg) feels livelier than a 200 PS family SUV (1,800 kg).
What is the most powerful production car in PS?
As of 2025, the Rimac Nevera holds the production EV record at 1,914 PS (1,408 kW). For combustion engines, the Bugatti Chiron Super Sport delivers 1,600 PS. Koenigsegg's Jesko Absolut produces 1,600 PS. But the real mind-bender is that a Formula 1 car's power unit produces about 1,050 PS from just 1.6 liters — over 650 PS per liter, achieved through turbocharging and energy recovery systems at 15,000 RPM.
Why is metric horsepower slightly less than British horsepower?
Because they're defined differently. British hp = 550 ft·lbf/s = 745.7 W. Metric hp = 75 kgf·m/s = 735.5 W. The metric definition uses round metric numbers (75 kg, 1 m, 1 s) rather than being an exact conversion of the British unit. The ~1.4% gap is small enough that it rarely matters practically, but it means a car rated at 200 PS is technically 197 hp. Marketing departments sometimes quietly use whichever number is larger.
Do electric cars use PS or kW for their power ratings?
Both, depending on market. Tesla lists kW in tech specs but PS/hp in consumer marketing because buyers understand horsepower intuitively. A Tesla Model 3 Performance produces about 460 PS (340 kW). The shift toward kW is accelerating because EVs make the kW connection obvious — if you charge at 11 kW and your motor outputs 150 kW, the relationship is clear. Eventually kW may replace PS entirely, but decades of "how many horses?" thinking won't die easily.
Foot pounds-force second – Frequently Asked Questions
Why is horsepower defined as exactly 550 ft·lbf/s?
James Watt calculated that a mill horse could turn a mill wheel 144 times per hour, doing 32,572 ft·lbf of work per minute — he rounded up to 33,000 ft·lbf/min (550 ft·lbf/s) for marketing purposes. He wanted to sell steam engines by comparing them to horses, so he likely overestimated the horse to make his engines look like better value. A real horse sustains closer to 350–500 ft·lbf/s, so Watt's "1 HP" is actually more than one horse.
How do you calculate ft·lbf/s from torque and RPM?
Power (ft·lbf/s) = Torque (ft·lbf) × RPM × 2π / 60. This is the workhorse formula (pun intended) of US mechanical engineering. For example, an engine producing 200 ft·lbf of torque at 3,000 RPM delivers 200 × 3,000 × 6.2832 / 60 = 62,832 ft·lbf/s ≈ 114 hp. The formula works because angular velocity in rad/s times torque in ft·lbf gives power directly in ft·lbf/s.
What everyday forces produce 1 ft·lbf/s of power?
Pushing with 1 pound of force at 1 foot per second — roughly the effort of slowly sliding a light book across a table against friction. Lifting a 1-pound weight 1 foot in 1 second. Turning a doorknob with a very light touch. It's about 1.36 watts — enough to dimly light an LED. In human terms, it's almost effortless: casual walking produces about 50–80 ft·lbf/s of mechanical power, and you don't even notice.
Is ft·lbf/s still used in modern American engineering?
Yes, particularly in ballistics (muzzle energy rates), mechanical testing (dynamometer output), agricultural machinery specs, and industrial equipment designed for the US market. However, even in the US, many engineering firms are switching to SI units for international compatibility. The automotive industry increasingly quotes power in both hp and kW. Aerospace has been mostly metric since the 1990s. Ft·lbf/s survives mainly in traditional mechanical and manufacturing industries.
How does ft·lbf/s relate to bullet kinetic energy?
Bullets are rated in ft·lbf of muzzle energy (not per second), but the power of a firearm is the muzzle energy divided by barrel time. A .308 rifle bullet exits with about 2,600 ft·lbf of energy over a barrel transit time of ~0.001 seconds, meaning the instantaneous power is roughly 2,600,000 ft·lbf/s (about 3,500 hp). That's why rifle recoil feels punchy — for a millisecond, you're absorbing the reaction force of a truck engine.