Millimetre

1 millimetre =
International units
1×10−3 m 1×10−6 km
mm 10×106 Å
6.685×10−15 AU 105.7×10−21 LY
US customary / Imperial units
39.37×10−3 in 3.281×10−3 ft
1.094×10−3 yd 621.371×10−9 mi

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.

micrometre << millimetre << centimetre << decimetre << metre << decametre << kilometre

Equivalence to other units of length

1 millimetre is equal to:

• 0.001 metres, which can be represented by 1 E-3 m (1 metre is equal to 1,000 millimetres)
• 0.1 centimetres (1 centimetre is equal to 10 millimetres)
• about 0.03937 international inches (1 international inch is equal to 25.4 millimetres exactly)

Unicode symbols

For the purposes of compatibility with Chinese, Japanese and Korean (CJK) characters, Unicode has symbols for:

• millimetre (㎜) - code 339C
• square millimetre (㎟) - code 339F
• cubic millimetre (㎣) - code 33A3

They are useful only with East Asian fixed-width CJK fonts, because they are equal in size to one Chinese character.