Convert centimeters to millimeters instantly. Enter a value below, or use the formula and reference table further down the page.
In practice
Centimetres to millimetres is the simplest metric step: multiply by 10, because a centimetre is exactly ten millimetres. It matters most where precision changes the answer — drill bits, fasteners, screen protectors, jewellery and 3D-printing tolerances are all specified in millimetres, while rulers and tape measures for everyday use are marked in centimetres. A practical habit is to move the decimal point one place right and double-check the units on the product: a 6.5 cm item is 65 mm, and a part listed as 6.5 mm is ten times smaller than one listed as 6.5 cm.
How to convert centimeters to millimeters
Multiply the value by 10.
mm = cm × 10Example: 10 cm = 100 mm.
Centimeters to Millimeters conversion table
| Centimeters (cm) | Millimeters (mm) |
|---|---|
| 1 cm | 10 mm |
| 2 cm | 20 mm |
| 3 cm | 30 mm |
| 4 cm | 40 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 |
Frequently asked questions
How many millimeters is 1 centimeter?
1 centimeter equals 10 millimeters.
What is the formula to convert cm to mm?
To convert cm to mm, multiply the value by 10. The full formula is: mm = cm × 10.
How do I convert millimeters back to centimeters?
Use the same calculator above and type your value into the millimeters field instead — it converts in both directions. Or use the reverse formula: cm = mm ÷ 10.
Is the cm to mm conversion exact?
The conversion factor used here (10) is the standard internationally defined value. Results on this page are rounded to four decimal places for readability.