Convert Millimeters to Centimeters
Millimeters to centimeters is a quick metric-to-metric conversion you'll use constantly when reading rulers, spec sheets, or manufacturing tolerances. One millimeter is exactly 0.1 centimeters.
Millimeters to Centimeters conversion table
| Millimeters (mm) | Centimeters (cm) |
|---|---|
| 1 | 0.1 |
| 2 | 0.2 |
| 3 | 0.3 |
| 5 | 0.5 |
| 10 | 1 |
| 20 | 2 |
| 50 | 5 |
| 100 | 10 |
| 500 | 50 |
| 1,000 | 100 |
The formula
To convert millimeters to centimeters, multiply the length in millimeters by 0.1:
centimeters = millimeters × 0.1
A worked example
Converting 100 mm into centimeters:
100 × 0.1 = 10 cm
The same pattern holds at smaller values: 10 mm is 1 cm, and 5 mm is 0.5 cm.
When you'll use it
Reading a caliper or ruler measurement, converting a part tolerance from a manufacturing drawing, or simplifying a fine-grained millimeter measurement into the more commonly used centimeter. Because the factor is a clean 0.1, this conversion is easy to do without a calculator.
Frequently asked questions
How many centimeters are in a millimeter?
Exactly 0.1 centimeters. This is exact because the metric system defines 10 millimeters as one centimeter, with no rounding.
Is the millimeter to centimeter conversion exact?
Yes, always. Both units share the same metric base, so converting between them is just shifting the decimal point — there's no approximation.
How do I convert millimeters to centimeters in my head?
Move the decimal point one place to the left, or divide by 10. 45 mm becomes 4.5 cm, 120 mm becomes 12 cm.