Cm to mm
One cm equals 10 mm. 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
| cm | mm |
|---|---|
| 1 cm | 10 mm |
| 2 cm | 20 mm |
| 3 cm | 30 mm |
| 5 cm | 50 mm |
| 10 cm | 100 mm |
| 15 cm | 150 mm |
| 20 cm | 200 mm |
| 25 cm | 250 mm |
| 50 cm | 500 mm |
| 100 cm | 1000 mm |
| 500 cm | 5000 mm |
| 1000 cm | 10000 mm |
How to use
- Enter the number of cm in the field.
- The result in mm 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: mm = cm × 10. Going back the other way, one mm is 0.1 cm.
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.
mm = cm × 10
Frequently asked questions
How many mm are in one cm?
One cm is 10 mm.
How do I convert cm to mm?
Multiply by the factor: mm = cm × 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 mm back to cm?
One mm is 0.1 cm — or open the reverse page linked below.