Conversion formula

The conversion factor from centimeters to millimeters is 10, which means that 1 centimeter is equal to 10 millimeters:

1 cm = 10 mm

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

1 cm → 10 mm

640 cm → L_(mm)

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

L_(mm) = 640 cm × 10 mm

L_(mm) = 6400 mm

The final result is:

640 cm → 6400 mm

We conclude that 640 centimeters is equivalent to 6400 millimeters:

640 centimeters = 6400 millimeters

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 millimeter is equal to 0.00015625 × 640 centimeters.

Another way is saying that 640 centimeters is equal to 1 ÷ 0.00015625 millimeters.

Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that six hundred forty centimeters is approximately six thousand four hundred millimeters:

640 cm ≅ 6400 mm

An alternative is also that one millimeter is approximately zero times six hundred forty centimeters.

Conversion table

centimeters to millimeters chart

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