Feet per Second to Miles per Hour

Feet per second and miles per hour

A foot per second is exactly 0.3048 meters per second. Projectile and arrow speeds, water flow and some US engineering calculations use feet per second (fps).

A mile per hour is one international mile per hour: exactly 0.44704 m/s, or 1.609344 km/h. Speed limits and speedometers in the US and UK, and pitch speeds in baseball, use mph.

Worked example

Convert 1,000 ft/s: 1,000 × 0.6818181818 = 681.8181818, so 1,000 feet per second is 681.8181818 miles per hour. Likewise 2,000 ft/s = 1,363.636364 mph.

Estimating in your head

Multiply by 0.68 for a quick figure; it is off by about 0.3%. For 1,000 ft/s that gives 680 mph, against 681.818 exactly.

Going the other way

To convert miles per hour to feet per second, divide by 0.6818181818 (or multiply by 1.46666666667). The swap button between the boxes opens that page.

mph = ft/s × 0.6818181818

1 ft/s = 0.3048 m/s and 1 mph = 0.44704 m/s, both by definition, so the factor is their ratio: 0.6818181818 (rounded here; the page uses the full value). Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.