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 421.5 feet per second into miles per hour we have to multiply 421.5 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

421.5 ft/s → V_(mph)

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

V_(mph) = 421.5 ft/s × 0.68181818181818 mph

V_(mph) = 287.38636363636 mph

The final result is:

421.5 ft/s → 287.38636363636 mph

We conclude that 421.5 feet per second is equivalent to 287.38636363636 miles per hour:

421.5 feet per second = 287.38636363636 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 0.0034796362198497 × 421.5 feet per second.

Another way is saying that 421.5 feet per second is equal to 1 ÷ 0.0034796362198497 miles per hour.

Approximate result

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

421.5 ft/s ≅ 287.386 mph

An alternative is also that one mile per hour is approximately zero point zero zero three times four hundred twenty-one point five 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