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A centimetre (International spelling) or centimeter (American English), with SI symbol cm, is a unit of length in the International System of Units (SI) equal to one hundredth of a metre, centi- being the SI prefix for a factor of Template:Sfrac.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Equivalently, there are 100 centimetres in 1 metre. The centimetre was the base unit of length in the now deprecated centimetre–gram–second (CGS) system of units.
Though for many physical quantities, SI prefixes for factors of 103—like milli- and kilo-—are often preferred by technicians, the centimetre remains a practical unit of length for many everyday measurements; for instance, human height is commonly measured in centimetres.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Cite book</ref> A centimetre is approximately the width of the fingernail of an average adult person.
Equivalence to other units of lengthEdit
| Template:Calculator centimetre | = Template:Calculator millimetres |
| = Template:Calculator metres | |
| = Template:Calculator inches (There are exactly 2.54 centimetres in one inch.) |
One millilitre is defined as one cubic centimetre, under the SI system of units.
Other usesEdit
In addition to its use in the measurement of length, the centimetre is used:
- sometimes, to report the level of rainfall as measured by a rain gauge<ref>{{#invoke:citation/CS1|citation
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- in the CGS system, the centimetre is used to measure capacitance, where 1 cm of capacitance = Template:Val farads<ref>{{#invoke:citation/CS1|citation
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- in maps, centimetres are used to make conversions from map scale to real world scale (kilometres)
- to represent second moment of areas (cm4)
- as the inverse of the Kayser, a CGS unit, and thus a non-SI metric unit of wavenumber: 1 kayser = 1 wave per centimetre; or, more generally, (wavenumber in kaysers) = 1/(wavelength in centimetres). The SI unit of wavenumber is the inverse metre, m−1.
Unicode symbolsEdit
For the purposes of compatibility with Chinese, Japanese and Korean (CJK) characters, Unicode has symbols for:<ref>CJK Compatibility excerpt from The Unicode Standard, Version 10.0.</ref>
- centimetre – Template:Unichar
- square centimetre – Template:Unichar
- cubic centimetre – Template:Unichar
These characters are each equal in size to one Chinese character and are typically used only with East Asian, fixed-width CJK fonts.