# ››Convert millimetre to inch

 mm inches

 Did you mean to convert megametre millimetre to inches

How many mm in 1 inches? The answer is 25.4.
We assume you are converting between millimetre and inch.
You can view more details on each measurement unit:
mm or inches
The SI base unit for length is the metre.
1 metre is equal to 1000 mm, or 39.3700787402 inches.
Note that rounding errors may occur, so always check the results.
Use this page to learn how to convert between millimetres and inches.
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# ››Definition: Millimeter

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.

# ››Definition: Inch

An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot. The inch is usually the universal unit of measurement in the United States, and is widely used in the United Kingdom, and Canada, despite the introduction of metric to the latter two in the 1960s and 1970s, respectively. The inch is still commonly used informally, although somewhat less, in other Commonwealth nations such as Australia; an example being the long standing tradition of measuring the height of newborn children in inches rather than centimetres. The international inch is defined to be equal to 25.4 millimeters.

# ››Metric conversions and more

ConvertUnits.com provides an online conversion calculator for all types of measurement units. You can find metric conversion tables for SI units, as well as English units, currency, and other data. Type in unit symbols, abbreviations, or full names for units of length, area, mass, pressure, and other types. Examples include mm, inch, 100 kg, US fluid ounce, 6'3", 10 stone 4, cubic cm, metres squared, grams, moles, feet per second, and many more!