To convert millimeters to centimeters (mm to cm), multiply by 0.1. 1 millimeter equals 0.1 cm, about 17% of a grain of rice.
| millimeters | centimeters |
|---|---|
| 1 millimeter | 0.1 cm |
| 2 millimeters | 0.2 cm |
| 5 millimeters | 0.5 cm |
| 10 millimeters | 1 cm |
| 25 millimeters | 2.5 cm |
| 50 millimeters | 5 cm |
| 100 millimeters | 10 cm |
| 250 millimeters | 25 cm |
| 500 millimeters | 50 cm |
| 1000 millimeters | 100 cm |
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.
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.