How many um in 1 millimetre?
The answer is 1000.
We assume you are converting between micrometre and millimetre.
You can view more details on each measurement unit:
um or millimetre
The SI base unit for length is the metre.
1 metre is equal to 1000000 um, or 1000 millimetre.
Note that rounding errors may occur, so always check the results.
Use this page to learn how to convert between micrometres and millimetres.
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A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the size of a droplet of mist or fog. It is also commonly known as a micron, although that term is officially outdated. It can be written in the expanded mathmatical notation (1×10-6 m)
The symbol µ is the "micro sign", which should look identical to the Greek letter mu (?) (the two may or may not look the same, depending on the font). The symbol "um" is sometimes used, when the µ and ? are not available, for example when using a typewriter.
The micrometre is a common unit of measurement for wavelengths of infrared radiation. Some people (especially in astronomy and the semiconductor business) use the old name micron and/or the solitary symbol µ (both of which were official between 1879 and 1967) to denote a micrometre. This practice persists in the face of official discouragement, perhaps to help disambiguate between the unit of measurement and the micrometer, a measuring device.
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.
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