Length Conversion Formulas

Conversion from	to	Formula
Millimetres	Inches	in = 0.03937 x mm
Inches	Millimetres	mm = 25.4 x in
Millimetres	Metres	m = 0.001 x m

A millimetre (American spelling: millimeter, symbol mm) is a unit of length that is equal to one thousandth of a metre, the current 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 << 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)

Uses of millimetre

---

In addition to its use in the measurement of length, the millimetre is used:

• to report the level of rainfall as measured with a rain gauge.

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.

See also

---

• 1 E-3 m
• SI
• SI prefix
• Metric system
• Orders of magnitude
• Conversion of units, for comparison with other units of length

References

---

• CJK Compatibility excerpt from The Unicode Standard, Version 4.1.

Units of length

Millimeter | Millimeter | Millimeeter | Milimetro | Milímetro | Millimetri | Milimetrs | ミリメートル | Millimeter | Millimeter | Millimeter | Milimetr | Миллиметр | Milimeter | Millimeter | Milimét