## Conversion formula

The conversion factor from feet per second to miles per hour is 0.68181818181818, which means that 1 foot per second is equal to 0.68181818181818 miles per hour:

1 ft/s = 0.68181818181818 mph

To convert 21 feet per second into miles per hour we have to multiply 21 by the conversion factor in order to get the velocity amount from feet per second to miles per hour. We can also form a simple proportion to calculate the result:

1 ft/s → 0.68181818181818 mph

21 ft/s → V(mph)

Solve the above proportion to obtain the velocity V in miles per hour:

V(mph) = 21 ft/s × 0.68181818181818 mph

V(mph) = 14.318181818182 mph

The final result is:

21 ft/s → 14.318181818182 mph

We conclude that 21 feet per second is equivalent to 14.318181818182 miles per hour:

21 feet per second = 14.318181818182 miles per hour ## Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 mile per hour is equal to 0.06984126984127 × 21 feet per second.

Another way is saying that 21 feet per second is equal to 1 ÷ 0.06984126984127 miles per hour.

## Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that twenty-one feet per second is approximately fourteen point three one eight miles per hour:

21 ft/s ≅ 14.318 mph

An alternative is also that one mile per hour is approximately zero point zero seven times twenty-one feet per second.

## Conversion table

### feet per second to miles per hour chart

For quick reference purposes, below is the conversion table you can use to convert from feet per second to miles per hour

feet per second (ft/s) miles per hour (mph)
22 feet per second 15 miles per hour
23 feet per second 15.682 miles per hour
24 feet per second 16.364 miles per hour
25 feet per second 17.045 miles per hour
26 feet per second 17.727 miles per hour
27 feet per second 18.409 miles per hour
28 feet per second 19.091 miles per hour
29 feet per second 19.773 miles per hour
30 feet per second 20.455 miles per hour
31 feet per second 21.136 miles per hour