# Hexadecimal

In mathematics and computing, the **hexadecimal** (also **base 16** or simply **hex**) numeral system is a positional numeral system that represents numbers using a radix (base) of 16. Unlike the decimal system representing numbers using 10 symbols, hexadecimal uses 16 distinct symbols, most often the symbols "0"–"9" to represent values 0 to 9, and "A"–"F" (or alternatively "a"–"f") to represent values from 10 to 15.

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List of numeral systems |

Software developers and system designers widely use hexadecimal numbers because they provide a human-friendly representation of binary-coded values. Each hexadecimal digit represents four bits (binary digits), also known as a nibble (or nybble). For example, an 8-bit byte can have values ranging from 00000000 to 11111111 in binary form, which can be conveniently represented as 00 to FF in hexadecimal.

In mathematics, a subscript is typically used to specify the base. For example, the decimal value 6,849 would be expressed in hexadecimal as 1AC1_{16}. In programming, a number of notations are used to denote hexadecimal numbers, usually involving a prefix. The prefix `0x`

is used in C, which would denote this value as `0x1AC1`

.

Hexadecimal is used in the transfer encoding **Base16**, in which each byte of the plaintext is broken into two 4-bit values and represented by two hexadecimal digits.