# How to Convert Miles Per Hour to Feet Per Second

Updated on February 21, 2013

## By Joan Whetzel

Have you ever felt the need for speed? Some people have this love of speed more than others - race car drivers, baseball pitchers, jet pilots, rocket scientists. The speeds for such occupations are usually given as miles per hour (mph) in the US. However, sometimes the reading needs to be recorded in feet per second (ft./s). So how does the speed reading get converted from mph to ft/s?

Calculating Speed in Miles Per Hour (MPH) and Feet Per Second (Ft/S)

Both measurements, miles per hour and feet per second, are ratios of the distance traveled to the amount of time it takes to travel that distance. For mph, the distance is miles and the time is measured in hours, and the measurement establishes how many miles that racecar could drive in one hour's time. The metric equivalent would be kilometers per hour (kph). For ft/s the distance is feet and the time is measured in seconds. For ft/s, the measurement explains how many feet a rocket ship can cover every second. The metric equivalent is measured as meters per second.

The first step in converting any speed reading is to measure the speed of the object in motion (i.e. the baseball being hurled at the batter, the racecar tearing up the track, the rocket roaring into the sky) in miles per hour or feet per second. With the race car, the speed is measured by the car's speedometer and transmitted digitally to the driver's pit crew. The pitcher's throwing speed is recorded as the ball zips past a stationary camera and then is digitally analyzed to determine the speed. In the case of the space ship's thrusters, the velocity is measured electronically in feet per second and recorded at Mission Control. A low tech version for timing a foot race would be to measure out the distance that the runner covers (1 mile, 5 miles, a marathon) and timing that runner with a stop watch to figure out how long it takes the runner to cover the entire distance.

The next step is to divide the entire distance (26.2 miles) by the total time it took to cover that distance (4 hours) to determine the miles per hour: 26.2 miles / 4 hours = 6.55 mph. So that marathon runner averaged 6.55 miles per hour. Or a measurement of 5,280 feet in 5 seconds = 125,000 ft /5 seconds = 25,000 ft./s.

Converting from MPH to FT/S

To convert a miles per hour to ft/s reading the formula is ___mph x 3.2084 = ___ ft/s. In the case of the marathon runner who ran an average of 6.55 mph, the equation would read: 6.55 mph x 3.280840 = 28.49 ft/s.

Converting from FT/S to MPH

To convert from ft/s to mph, the formula is: ___ ft/s x 0.681818 = ___ mph. So for a rocket flying upward at 25,000 ft/s, the equation reads: 25,000 ft/s x 0.681818 = 17,045 mph.

Resources

Wikipedia. Miles Per Hour.

Healthy Living. How to Calculate Miles per Hour in Pitching.

Wikipedia. Foot per Second.

Calculator Pro. Feet per Second to Miles per Hour Calculator.

The Free Dictionary Online.

Calculator Pro. Miles per Hour to Feet per Second Calculator.

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