Hexadecimal (also base 16, or hexadecimal) is a positional numeral system with a radix, or base, of 16. Sixteen of these using symbols different, most often the symbols 0-9 to represent values zero to nine, and A, B, C, D, E, F (or a through f) to represent the values ten to fifteen. For example, hexadecimal numbers are the same 2AF3, in decimal, for (2 × 163) + (10 × 162) + (15 × 16) + 3, or 10.995.

Each hexadecimal digit represents four binary digits (bits) (also called a "bite"), and the main use hexadecimal notation is a human-friendly representation of the values of binary code in computer and digital electronics. For example, byte values can range from 0-255 (decimal) but may be more easily represented as two hexadecimal digits in the range 00 to FF. Hexadecimal is also commonly used to represent the memory address of the computer.