A centimeter is defined as exactly 10 millimeters — a simple, fixed metric-prefix conversion.
How it works
Multiplying centimeters by 10 gives millimeters; dividing millimeters by 10 gives centimeters back. Type into either field and the other updates instantly.
What this does not include
This does not include inches — for that, use this site’s cm-to-in or mm-to-inches calculators instead.
How to use this calculator
- Enter a value in either centimeters or millimeters — the other field fills in automatically.
Frequently asked questions
Where is this conversion most commonly needed?
Precision measurements in engineering, sewing, and reading product specifications given in one metric unit but needed in the other.
Why is a centimeter exactly 10 millimeters?
Both are metric-prefix units built on powers of ten from the base meter, making the relationship a clean, fixed ratio.
Which unit is more precise for small measurements?
Millimeters — a finer subdivision than centimeters, useful when a measurement needs more precision than whole or half centimeters allow.
