CM to MM Converter
Convert centimeter to millimeter instantly. 1 cm = 10 mm, worked steps and a full reference table.
How to use it
- Type the value in centimeter — the result updates as you type.
- Use Swap to flip the direction, or change either dropdown to convert between any two units.
- Click the result to copy it. The URL updates too, so you can bookmark or share the exact conversion.
Examples
| 1 cm | 10 mm |
| 5 cm | 50 mm |
| 10 cm | 100 mm |
| 100 cm | 1000 mm |
One centimeter equals 10 millimeters (mm). To convert centimeters to millimeters, multiply by 10; to go back the other way, multiply by 0.1 instead.
The converter above does it as you type and shows the working underneath, so you can check the arithmetic rather than take the number on trust.
What centimeters and millimeters actually measure
Centimeter (cm) — A centimetre is a hundredth of a metre. Body measurements, clothing sizes, paper and furniture dimensions across most of the world.
Millimeter (mm) — A millimetre is a thousandth of a metre, and the smallest division on a normal ruler. Engineering drawings, timber and steel sizes, rainfall and screen bezels.
CM to MM conversion table
The most common values, worked out in advance. Anything not listed can be typed straight into the converter.
| cm | mm |
|---|---|
| 1 cm | 10 mm |
| 2 cm | 20 mm |
| 5 cm | 50 mm |
| 10 cm | 100 mm |
| 25 cm | 250 mm |
| 50 cm | 500 mm |
| 100 cm | 1000 mm |
How to convert centimeters to millimeters by hand
Multiply the number of centimeters by 10.
For example, 25 cm × 10 = 250 mm.
Going the other way, divide by 10 — or multiply by 0.1, which is the same thing and easier to do in your head.
Everything runs in your browser
There is no server involved in the calculation. The numbers you type never leave your device, nothing is logged, and the page keeps working with no connection once it has loaded. That is not a marketing line — it is simply how the tool is built, because a calculation like this has no reason to touch a network.
Questions people ask
How many mm are in 1 cm?
1 cm equals exactly 10 mm. Multiply any value in centimeter by 10 to get millimeter.
Is anything uploaded to a server?
No. The whole calculation happens in your browser. Nothing is sent anywhere, and the page keeps working offline once loaded.
Last updated 18 August 2026