Conversion formula

The conversion factor from millimeters to kilometers is 1.0E-6, which means that 1 millimeter is equal to 1.0E-6 kilometers:

1 mm = 1.0E-6 km

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

1 mm → 1.0E-6 km

640 mm → L_(km)

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

L_(km) = 640 mm × 1.0E-6 km

L_(km) = 0.00064 km

The final result is:

640 mm → 0.00064 km

We conclude that 640 millimeters is equivalent to 0.00064 kilometers:

640 millimeters = 0.00064 kilometers

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 kilometer is equal to 1562.5 × 640 millimeters.

Another way is saying that 640 millimeters is equal to 1 ÷ 1562.5 kilometers.

Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that six hundred forty millimeters is approximately zero point zero zero one kilometers:

640 mm ≅ 0.001 km

An alternative is also that one kilometer is approximately one thousand five hundred sixty-two point five times six hundred forty millimeters.

Conversion table

millimeters to kilometers chart

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