Conversion formula

The conversion factor from kilometers to miles is 0.62137119223733, which means that 1 kilometer is equal to 0.62137119223733 miles:

1 km = 0.62137119223733 mi

To convert 640 kilometers into miles we have to multiply 640 by the conversion factor in order to get the length amount from kilometers to miles. We can also form a simple proportion to calculate the result:

1 km → 0.62137119223733 mi

640 km → L_(mi)

Solve the above proportion to obtain the length L in miles:

L_(mi) = 640 km × 0.62137119223733 mi

L_(mi) = 397.67756303189 mi

The final result is:

640 km → 397.67756303189 mi

We conclude that 640 kilometers is equivalent to 397.67756303189 miles:

640 kilometers = 397.67756303189 miles

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 mile is equal to 0.0025146 × 640 kilometers.

Another way is saying that 640 kilometers is equal to 1 ÷ 0.0025146 miles.

Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that six hundred forty kilometers is approximately three hundred ninety-seven point six seven eight miles:

640 km ≅ 397.678 mi

An alternative is also that one mile is approximately zero point zero zero three times six hundred forty kilometers.

Conversion table

kilometers to miles chart

For quick reference purposes, below is the conversion table you can use to convert from kilometers to miles