**hexadecimal**(also

**base 16**, or

**hex**) is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols

**0**–

**9**to represent values zero to nine, and

**A**–

**F**(or alternatively

**a**–

**f**) to represent values ten to fifteen.

Hexadecimal numerals are widely used by computer system designers and programmers, as they provide a more human-friendly representation of binary-coded values. Each hexadecimal digit represents four binary digits, also known as a nibble, which is half a byte. For example, a single byte can have values ranging from 0000 0000 to 1111 1111 in binary form, which can be more conveniently represented as 00 to FF in hexadecimal.

In mathematics, a subscript is typically used to specify the radix. For example the decimal value 10,995 would be expressed in hexadecimal as 2AF3

_{16}. In programming, a number of notations are used to support hexadecimal representation, usually involving a prefix or suffix. The prefix

`0x`

is used in C and related languages, which would denote this value by 0x2AF3.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.