Enter a number in any base — binary, decimal, octal or hex — and see it converted to all four at once.
Programmers move between number bases constantly: decimal for everyday maths, binary for bit-level work, hexadecimal for colours, memory addresses and byte values, and occasionally octal for things like Unix file permissions. Pick the base you're starting from, type your value, and all four representations appear together. Tap any result to copy it.
Hexadecimal is popular because each hex digit maps neatly to exactly four binary bits, making it a compact, readable stand-in for binary — which is why colour codes (#FF8800) and byte values use it. Seeing a number in all bases side by side makes those relationships obvious and saves you from reaching for a calculator or writing a quick script.