Conversion formula

The conversion factor from feet per second to kilometers per hour is 1.0972799999991, which means that 1 foot per second is equal to 1.0972799999991 kilometers per hour:

1 ft/s = 1.0972799999991 km/h

To convert 399.9 feet per second into kilometers per hour we have to multiply 399.9 by the conversion factor in order to get the velocity amount from feet per second to kilometers per hour. We can also form a simple proportion to calculate the result:

1 ft/s → 1.0972799999991 km/h

399.9 ft/s → V_(km/h)

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

V_(km/h) = 399.9 ft/s × 1.0972799999991 km/h

V_(km/h) = 438.80227199965 km/h

The final result is:

399.9 ft/s → 438.80227199965 km/h

We conclude that 399.9 feet per second is equivalent to 438.80227199965 kilometers per hour:

399.9 feet per second = 438.80227199965 kilometers per hour

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 kilometer per hour is equal to 0.0022789307708981 × 399.9 feet per second.

Another way is saying that 399.9 feet per second is equal to 1 ÷ 0.0022789307708981 kilometers per hour.

Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that three hundred ninety-nine point nine feet per second is approximately four hundred thirty-eight point eight zero two kilometers per hour:

399.9 ft/s ≅ 438.802 km/h

An alternative is also that one kilometer per hour is approximately zero point zero zero two times three hundred ninety-nine point nine feet per second.

Conversion table

feet per second to kilometers per hour chart

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