## 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 40 centimeters into millimeters we have to multiply 40 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

40 cm → L(mm)

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

L(mm) = 40 cm × 10 mm

L(mm) = 400 mm

The final result is:

40 cm → 400 mm

We conclude that 40 centimeters is equivalent to 400 millimeters:

40 centimeters = 400 millimeters ## Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 millimeter is equal to 0.0025 × 40 centimeters.

Another way is saying that 40 centimeters is equal to 1 ÷ 0.0025 millimeters.

## Approximate result

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

40 cm ≅ 400 mm

An alternative is also that one millimeter is approximately zero point zero zero three times 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

centimeters (cm) millimeters (mm)
41 centimeters 410 millimeters
42 centimeters 420 millimeters
43 centimeters 430 millimeters
44 centimeters 440 millimeters
45 centimeters 450 millimeters
46 centimeters 460 millimeters
47 centimeters 470 millimeters
48 centimeters 480 millimeters
49 centimeters 490 millimeters
50 centimeters 500 millimeters