Metric length converter
Millimeters to Centimeters Converter
Enter either measurement to convert millimeters and centimeters instantly. No upload or account is needed.
How to convert millimeters to centimeters
Milli means one-thousandth and centi means one-hundredth of a meter, so one centimeter contains exactly ten millimeters.
centimeters = millimeters ÷ 10
millimeters = centimeters × 10
10 millimeters = 1 centimeter exactly
Example: 25 mm ÷ 10 = 2.5 cm. In reverse, 2.5 cm × 10 = 25 mm.
When mm-to-cm conversion helps
Both units are metric, but specifications often choose a different scale depending on the object.
Product dimensions
Compare a millimeter specification with a ruler or listing marked in centimeters.
School and science work
Change between neighboring metric units without approximating the answer.
Crafts and small parts
Translate material thickness, bead size, or component width into the more convenient unit.
Common millimeters to centimeters chart
These values use the exact ten-to-one metric relationship.
| Millimeters (mm) | Centimeters (cm) |
|---|---|
| 1 | 0.10 |
| 2 | 0.20 |
| 5 | 0.50 |
| 10 | 1.00 |
| 12 | 1.20 |
| 15 | 1.50 |
| 20 | 2.00 |
| 25 | 2.50 |
| 30 | 3.00 |
| 50 | 5.00 |
| 75 | 7.50 |
| 100 | 10.00 |
| 150 | 15.00 |
| 250 | 25.00 |
| 1000 | 100.00 |
Exact conversion and display precision
Dividing by ten is exact. The decimal-place menu changes only how many digits the page displays after the decimal point.
A trailing zero does not change the size: 2.5 cm and 2.50 cm are the same length. Extra displayed digits should not be treated as extra measuring accuracy.
Keep the precision supplied by the original measurement when the value is used for a drawing, tolerance, or manufacturing decision.
Sources and method
The unit constants come from the primary standards below. ToolNeko applies those constants in a browser-only calculation, then rounds only the displayed result.
- NIST — SI Units: Length Explains metric length units and states that 10 millimeters make 1 centimeter.
- NIST — Metric SI Prefixes Defines milli as 10⁻³ and centi as 10⁻².
Frequently asked questions
How do I convert millimeters to centimeters?
Divide millimeters by 10. For example, 86 mm ÷ 10 = 8.6 cm.
How many millimeters are in one centimeter?
There are exactly 10 millimeters in one centimeter.
Is 1 mm equal to 0.1 cm?
Yes. One millimeter is exactly one-tenth of a centimeter.
How do I convert centimeters back to millimeters?
Multiply centimeters by 10. For example, 4.2 cm × 10 = 42 mm.