**Full name:** millimetre

**Plural form:** millimetres

**Symbol:** mm

**Alternate spelling:** millimeters

**Category type:** length

**Scale factor:** 0.001

The SI base unit for length is the metre.

1 metre is equal to 1000 millimeter.

Valid units must be of the **length** type.

You can use this form to select from known units:

A millimetre (American spelling: millimeter, symbol mm) is one thousandth of a metre, which is the International System of Units (SI) base unit of length. The millimetre is part of a metric system. A corresponding unit of area is the square millimetre and a corresponding unit of volume is the cubic millimetre.

millimeter to mile [nautical, international]

millimeter to stadium

millimeter to fathom

millimeter to foot [pre-1963 Canada]

millimeter to didot point

millimeter to ell [English]

millimeter to dra [Iraq]

millimeter to city block [Midwest U.S.]

millimeter to click [U.S. military]

millimeter to smoot