Mm to cm
One mm equals 0.1 cm. Type any number and the answer appears as you type — the maths happens in your browser.
Result
The same value in every unit
| Unit | Value |
|---|
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Common values
| mm | cm |
|---|---|
| 1 mm | 0.1 cm |
| 2 mm | 0.2 cm |
| 3 mm | 0.3 cm |
| 5 mm | 0.5 cm |
| 10 mm | 1 cm |
| 15 mm | 1.5 cm |
| 20 mm | 2 cm |
| 25 mm | 2.5 cm |
| 50 mm | 5 cm |
| 100 mm | 10 cm |
| 500 mm | 50 cm |
| 1000 mm | 100 cm |
How to use
- Enter the number of mm in the field.
- The result in cm updates on every keystroke.
- Use the table below for the values people look up most often.
Formula and reverse conversion
The formula
To convert by hand: cm = mm ÷ 10. Going back the other way, one cm is 10 mm.
Metric units differ by powers of ten
Both units belong to the metric system, so the conversion is a shift of the decimal point: the factor is a power of ten and nothing is lost to rounding.
cm = mm ÷ 10
Frequently asked questions
How many cm are in one mm?
One mm is 0.1 cm.
How do I convert mm to cm?
Multiply by the factor: cm = mm ÷ 10.
Is the result exact?
The factors are the exact legal definitions, and up to ten significant digits are kept in the answer. Rounding happens only in the display.
How do I convert cm back to mm?
One cm is 10 mm — or open the reverse page linked below.