十进制是以10为基础的数字系统。

十进制有两大类：

十进制包括十进位制，但不等同十进位制。

This article aims to be an accessible introduction. For the mathematical definition, see Decimal representation.

The decimal numeral system (also called base 10 or occasionally denary) has ten as its base. It is the numerical base most widely used by modern civilizations.

Decimal notation often refers to a base 10 positional notation such as the Hindu-Arabic numeral system or rod calculus; however, it can also be used more generally to refer to non-positional systems such as Roman or Chinese numerals which are also based on powers of ten.