Centimetre
A centimetre (international spelling) or centimeter (American spelling) (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 1/100. 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 most commonly measured in centimetres. A centimetre is approximately the width of the fingernail of an average adult person.
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| = 10 millimetres |
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| = 0.01 metres |
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| = 0.393700787401574803149606299212598425196850 inches |
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| (There are exactly 2.54 centimetres in one inch.) |
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| One millilitre is defined as one cubic centimetre, under the SI system of units. |
| 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 |
| in the CGS system, the centimetre is used to measure capacitance, where 1 cm of capacitance = 1.113e-12 farads |
| 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. |
| For the purposes of compatibility with Chinese, Japanese and Korean (CJK) characters, Unicode has symbols for: |
| centimetre – |
| square centimetre – |
| cubic centimetre – |
| They are mostly used only with East Asian fixed-width CJK fonts, because they are equal in size to one Chinese character. |
