Centimeter (cm)
The centimeter is a metric unit of length equal to one-hundredth of a meter or 10 millimeters. Abbreviated as "cm", it is one of the most commonly used units for everyday small-to-medium measurements worldwide. From measuring body height in medical settings to sizing clothing, furniture dimensions, and school rulers, the centimeter is the go-to unit for lengths that are too large for millimeters yet too small for meters.
Definition
One centimeter equals exactly 0.01 meters, 10 millimeters, or 0.3937 inches. There are 100 centimeters in a meter and 2.54 centimeters in one inch (this exact relationship was established by the International Yard and Pound Agreement of 1959). The centimeter is not an SI base unit but is an accepted SI unit formed by applying the SI prefix "centi-" (meaning one-hundredth) to the base unit meter.
History
The centimeter emerged as part of the original metric system established during the French Revolution. When France introduced the meter in 1795, decimal prefixes were applied to create practical sub-multiples: the decimeter (1/10), the centimeter (1/100), and the millimeter (1/1,000). The CGS (centimeter-gram-second) system of units, introduced in 1874, made the centimeter a base unit for scientific work and dominated physics and engineering for decades. Although the SI system adopted in 1960 chose the meter as the base unit instead, the centimeter remained widely used in everyday measurement. Today it is the standard small-scale unit in virtually every metric country.
Common Uses
In most of the world, centimeters are used for body height measurements on medical charts, clothing sizes, waist and chest measurements, and shoe sizing charts. Furniture dimensions, TV bezels, and picture frame sizes are specified in centimeters. School rulers are typically 30 cm long. In science, centimeters appear in the CGS system that is still used in some fields of physics and astronomy. Rainfall is commonly reported in centimeters or millimeters. In Germany, Austria, and Switzerland, centimeters are the everyday unit for personal measurements and household dimensions.
Did You Know? Facts About Centimeter
- A standard credit card is 8.56 cm wide and 5.398 cm tall - a handy everyday reference for centimeters.
- The diameter of a Euro one-cent coin is 1.625 cm, making it close to a quick visual reference for one and a half centimeters.
- Snowfall is measured in centimeters in metric countries and in inches in the US - 10 cm of snow is roughly 4 inches.
- The CGS system used centimeters as its base length unit from 1874 until it was largely replaced by SI (using meters) in 1960.
- Human hair grows at roughly 1.25 cm per month, or about 15 cm per year.