Millimetre - Definition and Overview

A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre.

1 mm is equal to:

• about 0.03937 inches
• 0.1 cm

See 1 E-3 m for comparisons.

The level of rainfall is also reported as millimeters as measured with a rain gauge.

micrometre << millimetre << centimetre

Unicode has symbols for "mm" (㎜), for square millimetre (㎟) and for cubic millimetre (㎣).

See also

Orders of magnitude (length)