Home/Glossary/Hexadecimal (Base-16)

Hexadecimal (Base-16)

A numbering system using 16 symbols (0-9, A-F) commonly used in computing for compact binary representation.

Computer ScienceAlso called: "hex", "base16", "hexadecimal notation"

Hexadecimal (hex) provides human-readable representation of binary data.

Why hex is used

  • Compact: 1 hex digit = 4 bits, 2 hex digits = 1 byte.
  • Readable: Easier than binary (11111111 vs FF).
  • Alignment: Matches byte boundaries perfectly.

Common uses

  • Color codes: #FF5733 (RGB values in hex).
  • Memory addresses: 0x7FFF5FBFF710.
  • Character encodings: \x41 = 'A'.
  • Hash values: SHA-256 outputs as hex strings.
  • MAC addresses: 00:1A:2B:3C:4D:5E.

Conversion

  • Decimal 255 = Hex FF = Binary 11111111
  • Decimal 16 = Hex 10 = Binary 00010000
  • Decimal 42 = Hex 2A = Binary 00101010

Prefixes

  • 0x prefix (C, JavaScript): 0xFF
  • # prefix (CSS colors): #FF5733
  • \x prefix (escape sequences): \x41