To convert centimeters to millimeters (cm to mm), multiply by 10. 1 centimeter equals 10 mm, about 1.7 times as much as a grain of rice.
| centimeters | millimeters |
|---|---|
| 1 centimeter | 10 mm |
| 2 centimeters | 20 mm |
| 5 centimeters | 50 mm |
| 10 centimeters | 100 mm |
| 25 centimeters | 250 mm |
| 50 centimeters | 500 mm |
| 100 centimeters | 1,000 mm |
| 250 centimeters | 2,500 mm |
| 500 centimeters | 5,000 mm |
| 1000 centimeters | 10,000 mm |
Definition: 1/100 of a meter - the "centi" prefix doing the same job it does in "century" or "cent."
History: Introduced alongside the meter itself during the French Revolution's metric overhaul, the centimeter was designed from the start to be a convenient, everyday-sized subdivision - a meter is often too big and a millimeter too small for describing things like a person's height or a book's thickness.
Current use: Height, everyday object sizes, and fabric measurements across most of the world; also the standard unit doctors use internationally for body measurements.
Definition: 1/1000 of a meter - the same "milli" prefix as milliliter or milligram.
History: Like the centimeter, it arrived as part of the same 1790s French decimal system, built specifically to make precise, small-scale measurement simple - no more converting between competing local systems of inches, lines, and points.
Current use: Engineering tolerances, screen and camera specs, and rainfall measurements - which is why weather reports outside the US say "20mm of rain" rather than inches.