Base Converter

Convert integers between binary, octal, decimal, and hex. BigInt-based, arbitrary size.

What this tool does

Converts integers between binary, octal, decimal, and hexadecimal. Enter a value in any one base and get all the others at once, without switching modes. Conversion is instant and local — handy to keep pinned in a browser tab.

Typical use cases

Reading Linux permissions: each octal digit in chmod 755 maps to three rwx bits, obvious once you see it in binary. Debugging network protocols or file formats: hexadecimal offsets in the spec need converting to decimal array indices. Working with colors: #FF8800 is just three hexadecimal bytes. And for anyone studying computer architecture, base conversion is daily homework.

Caveats

Integers beyond JavaScript's safe range (2^53) lose precision — split 64-bit addresses or long hashes into chunks. Negative numbers are stored as two's complement in hardware, and languages display them differently in non-decimal bases (sign bit vs. complement); this tool converts the mathematical value. The 0x prefix on hexadecimal input is optional.