Base Converter
Input base
Binary
11111111Octal
377Decimal (input)
255Hexadecimal
ffEnter a number in binary, octal, decimal, or hexadecimal and see it instantly converted into all four bases at once. Supports arbitrarily large integers (using exact integer math, not floating point) and negative numbers with a leading minus sign.
Frequently asked questions
Why does my input show as invalid?
Each base only allows certain digits — binary allows just 0 and 1, octal allows 0-7, and hexadecimal allows 0-9 plus a-f. If your input contains a character outside that set for the selected input base, it can't be parsed.
Is there a limit to how large a number I can convert?
No practical limit — conversion uses arbitrary-precision integer arithmetic, so very large numbers (far beyond what a 64-bit integer can hold) convert exactly, without rounding errors.