Millimetre
| millimetre | |
|---|---|
 Ruler with millimetre and centimetre marks | |
| General information | |
| Unit system | SI |
| Unit of | Length |
| Symbol | mm |
| Named after | From metric prefix mille (Latin for "one thousand") and the metre |
| Conversions | |
| 1 mm in ... | ... is equal to ... |
| micrometres | 1000 |
| centimetres | 1/10 |
| metres | 1/1000 |
| kilometres | 1/1 000 000 |
| decimetres | 1/100 |
| inches | 0.039370 in |
| feet | 0.0032808 ft |
The millimetre (SI symbol: mm; international spelling) or millimeter (American spelling) is a unit of length in the International System of Units (SI), equal to one thousandth of a metre, the SI base unit of length.
- 1 metre = 1000 millimetres
- 1 centimetre = 10 millimetres
One millimetre is also equal to:
- 1000 micrometres
- 1000000 nanometres
Since an inch is officially defined as exactly 25.4 millimetres, 1 millimetre is precisely 5⁄127 inches (≈ 0.03937 inches).