Millimeters to Centimeters Converter

About the mm to cm calculation

One millimeter is exactly 0.1 centimeters, so converting between them is a single multiplication. Enter any value above and the result updates as you type. The standard fine unit on engineering drawings and rainfall figures. How height and clothing sizes are quoted almost everywhere outside the US.

Formula

cm = mm × 0.1

1 mm = 0.1 cm
1 cm = 10 mm

Worked example

To convert 100 mm, multiply by 0.1: 100 × 0.1 = 10 cm.

Frequently asked questions

How many centimeters are in a millimeter?

There are 0.1 centimeters in one millimeter. To convert any amount, multiply the number of millimeters by 0.1.

How do I convert centimeters back to millimeters?

Divide instead of multiplying, or equivalently multiply by 10. One centimeter is 10 millimeters.

Is this conversion exact?

Yes. Since the international agreement of 1959, the relationship between millimeters and centimeters is defined exactly rather than measured, so the only rounding here is in how many decimal places we show.

Where is each of these units used?

Millimeters: the standard fine unit on engineering drawings and rainfall figures. Centimeters: how height and clothing sizes are quoted almost everywhere outside the US.

Sources

• NIST Special Publication 811 — Guide for the Use of the International System of Units