Number Base Converter
About this tool
Computers count in binary, but humans read decimal — and programmers constantly meet hexadecimal in color codes (#ff8800), memory addresses, and hash digests. This converter translates a number between binary, octal, decimal, and hexadecimal in one click. It accepts common prefixes such as 0b, 0o, and 0x, ignores spaces and underscores, and uses arbitrary-precision integers, so even very large values convert exactly instead of losing precision the way floating-point math would. Typical uses: reading hex dumps while debugging, converting subnet masks, translating Unix file permissions (which are octal), and checking color values. Type the number, pick the base it is written in, and all four representations appear at once.
Privacy: all processing happens in your browser. Nothing is uploaded or stored.