Conversion formula

The conversion factor from millimeters to centimeters is 0.1, which means that 1 millimeter is equal to 0.1 centimeters:

1 mm = 0.1 cm

To convert 420 millimeters into centimeters we have to multiply 420 by the conversion factor in order to get the length amount from millimeters to centimeters. We can also form a simple proportion to calculate the result:

1 mm → 0.1 cm

420 mm → L_(cm)

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

L_(cm) = 420 mm × 0.1 cm

L_(cm) = 42 cm

The final result is:

420 mm → 42 cm

We conclude that 420 millimeters is equivalent to 42 centimeters:

420 millimeters = 42 centimeters

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 centimeter is equal to 0.023809523809524 × 420 millimeters.

Another way is saying that 420 millimeters is equal to 1 ÷ 0.023809523809524 centimeters.

Approximate result

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

420 mm ≅ 42 cm

An alternative is also that one centimeter is approximately zero point zero two four times four hundred twenty millimeters.

Conversion table

millimeters to centimeters chart

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