1 centimetre = 10 millimetres

Each number on a ruler represents 1 centimetre (cm).
The distance between the smallest lines on a ruler
is 1 millimetre (mm).

To convert your measurement from cm to mm, simply multiply the centimetre value by 10.

The Explanation

Centimetres and millimetres are both derived from a measurement of distance called a metre used in the metric system. The prefix centi- means “one-hundredth,” so there are 100 centimetres in every meter. The prefix milli- means “one-thousandth,” so there are 1000 millimetres in every meter. Millimetres and centimetres are only separated by one tens place, which means that there are ultimately 10 millimetres for every centimetre.

A Helpful Online Tool

A very helpful tool you can use for converting any metrics is UnitConverters.net. All you have to do is enter your centimetre value and click convert.