How to convert number bases
Convert a value between binary, octal, decimal, hexadecimal and any base from 2 to 36 at once — with exact big-integer math, so even huge numbers stay precise.
1. Type a number
Enter your value — for example 255, 0xFF or 0b1010.
2. Pick the base
Select the input base or use Auto-detect, which reads 0x, 0b and 0o prefixes.
3. Copy any result
All bases convert live; copy binary, hex, decimal, octal or a custom base with one click.
Programmers and students use base conversion for bitmasks and flags, color values (hex like #FF8800), memory addresses, file permissions (octal), networking, and low-level debugging. Common conversions include binary to decimal, decimal to binary, hex to decimal and decimal to hex. Because this tool uses big-integer arithmetic, values far beyond 64 bits convert exactly with no rounding errors.