Number Base Converter
Convert between decimal, binary, hexadecimal and octal.
How it works
Every base works the same way: each position is worth the base raised to its index. Binary counts in powers of two, hexadecimal in powers of sixteen.
Hex exists because it maps cleanly onto binary — one hex digit is exactly four bits, so a byte is always two hex digits and you can convert by eye once you know the sixteen patterns. Octal is three bits per digit and survives mostly in Unix file permissions, where three bits per group is exactly what is needed.