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 ⁠1 100⁠. [1] Free online ruler for accurate measuring in inches, centimeters, and millimeters. Use our real size digital ruler on any phone, tablet, or computer. centimetre (cm), unit of length equal to 0.01 metre in the metric system and the equivalent of 0.3937 inch. A centimeter (cm) is a metric unit of measurement used for measuring the length of an object. Learn about the tools, conversion charts, examples, & more. Centimeters to inches (cm to in) converter and how to convert. Definition: A centimeter (symbol: cm) is a unit of length in the International System of Units (SI), the current form of the metric system. It is defined as 1/100 meters. Units of length conversion charts are discussed here in metric units of length and customary units of length: In math when we use length, we know that the standard unit of length is ‘Metre’ which is written in short as ‘m’. A metre length is divided into 100 equal parts. 1cm is equivalent to 0.39370 inches. Origin: The metric, or decimal, system of weights and measures was defined and adopted in France in 1795. Using the metre as the basis for length measurements, the system is now used officially across the globe. The term cm is an abbreviation for centimeter, a unit of length in the metric system. It is widely used in scientific, mathematical, and everyday contexts to measure short distances or small lengths. A centimeter is a unit of measuring length under the metric system of measurement. It can be abbreviated as 'cm'. Learn everything about centimeters in this article.