Feet Per Second to MPH Calculator

Feet per second is the natural output of many speed measurements in the United States — radar guns at batting practice, police speed enforcement units, ballistics and projectile testing, and physics experiments all report velocity in fps. But most people interpret speed in miles per hour. Converting between the two is essential for sports analysts reporting pitch velocity in mph, engineers comparing motor and vehicle speeds, hunters and shooters comparing muzzle velocities, and physics students translating between measurement contexts. The conversion factor connects feet and miles (5,280 feet per mile) with seconds and hours (3,600 seconds per hour). This calculator divides any fps value by 1.46667 and returns the equivalent miles per hour to four decimal places, handling both slow walking speeds and supersonic projectile velocities.

MPH = FPS ÷ 1.46̄6̄ (the bar notation indicates that 6 repeats). The conversion factor is derived from the definitions of the two units: one mile equals 5,280 feet and one hour equals 3,600 seconds. Dividing 5,280 by 3,600 gives exactly 22/15 ≈ 1.46̄6̄, which is the number of feet per second contained in one mile per hour. To go from fps to mph, you divide by this factor, because a higher number of feet per second corresponds to fewer miles per hour. The calculator uses the decimal approximation 1.46667, which introduces a negligible error of less than 0.0002% compared to the exact fraction 22/15. The classic benchmark is 88 fps = exactly 60 mph, useful for confirming the conversion is correct.