Conversion formula

The conversion factor from feet per second to knots is 0.59248380129641, which means that 1 foot per second is equal to 0.59248380129641 knots:

1 ft/s = 0.59248380129641 kt

To convert 643.9 feet per second into knots we have to multiply 643.9 by the conversion factor in order to get the velocity amount from feet per second to knots. We can also form a simple proportion to calculate the result:

1 ft/s → 0.59248380129641 kt

643.9 ft/s → V_(kt)

Solve the above proportion to obtain the velocity V in knots:

V_(kt) = 643.9 ft/s × 0.59248380129641 kt

V_(kt) = 381.50031965476 kt

The final result is:

643.9 ft/s → 381.50031965476 kt

We conclude that 643.9 feet per second is equivalent to 381.50031965476 knots:

643.9 feet per second = 381.50031965476 knots

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 knot is equal to 0.0026212297827298 × 643.9 feet per second.

Another way is saying that 643.9 feet per second is equal to 1 ÷ 0.0026212297827298 knots.

Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that six hundred forty-three point nine feet per second is approximately three hundred eighty-one point five knots:

643.9 ft/s ≅ 381.5 kt

An alternative is also that one knot is approximately zero point zero zero three times six hundred forty-three point nine feet per second.

Conversion table

feet per second to knots chart

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