What is a Foot per Second?

Feet per second is the standard ballistics unit for projectile speeds, American sports analytics, and engineering. Bullet velocities are universally given in fps: a .22 LR bullet flies at about 1,200 fps, a 9 mm pistol round at 1,150 fps, and a high-velocity rifle round at 3,000 fps. American football and baseball analytics increasingly use fps for measuring throwing speed, ball exit velocity, and player movement. Engineering disciplines that retain US customary units (HVAC, civil engineering) often specify air or water flow speeds in fps. The unit relates to mph (1.467 fps = 1 mph), m/s (1 fps ≈ 0.305 m/s), and the knot (1 fps ≈ 0.592 kn). Outside ballistics and US sports, m/s and km/h dominate — but in their domains, fps remains entrenched in American technical practice.

Visual reference for how the foot per second relates to other speed units. Each row links to the full converter for that pair.

• US ballistics and firearms
• US civil-engineering flow rates
• Older US physics and engineering texts

• ✓1 ft/s = 0.3048 m/s = 1.097 km/h = 0.682 mph.
• ✓Multiplying ft/s by 0.682 gives mph.
• ✓US engineering often uses ft/s; metric countries use m/s.

• ✗Confusing ft/s with fps (frames per second in video/gaming).
• ✗Mixing ft/s with mph without conversion.
• ✗Using ft/s instead of m/s in international scientific contexts.