Hexadecimal is a number system in which each place has a value 16 times the value of the place at its right. Hexadecimal numbers are written using the symbols 0–9 and A–F (or a–f). The hexadecimal number 35B, for example, is equivalent to (3 × 256) + (5 × 16) + (11 × 1) = 859 in decimal.
Hexadecimal provides a convenient way to express binary numbers in modern computers in which a byte is almost always defined as containing eight binary digits. When showing the contents of computer storage – for example, when getting a core dump of storage in order to debug a new computer program or when expressing a string of text characters or a string of binary values – one hexadecimal digit can represent the arrangement of four binary digits. Two hexadecimal digits can represent eight binary digits, or a byte.