Centimeter (cm)
Definition
A centimeter (symbol cm) is a metric unit of length equal to one hundredth of a meter, or exactly 10 millimeters. It is widely used for everyday human-scale measurements such as height, clothing, and small object dimensions.
History
The centimeter joined the metric system as soon as the meter was defined in 1799, formed by combining the SI prefix centi (from Latin centum, one hundred) with the meter. It became the base length unit of the now-obsolete CGS system, which dominated physics from the 1870s until the SI was adopted in 1960.
Within the SI, centimeter remains in everyday use even though kilometer and millimeter are the preferred multiples in scientific writing. The 2019 SI revision did not change its magnitude; it remains 0.01 meters as derived from the speed-of-light definition of the meter.
Standard reference
Defined by the BIPM SI Brochure as 0.01 × the meter. Permitted for use with the SI in everyday contexts per NIST Special Publication 811.
Common conversions
| 1 cm | = 0.01 m |
|---|---|
| = 10 mm | |
| = 0.393701 in | |
| = 0.0328084 ft |