A single hex digit maps exactly to four bits, aligning naturally with binary.
One hex digit (0-F) corresponds to exactly four bits (a nibble), so long binary strings become short and readable.
Color codes #RRGGBB, memory addresses 0x1F4, byte values 0xFF and more all use hex.
0x means hex, 0b means binary and 0o means octal. This tool recognizes and ignores these prefixes automatically.