Number Base Converter
Convert numbers between binary, octal, decimal, hexadecimal and any base from 2 to 36 with big-integer precision.
How it works
Type a number, pick the base it is written in, and every other representation updates as
you type — binary, octal, decimal, hexadecimal, base 32, base 36 and any custom radix
from 2 to 36. Digits use the usual 0–9 then a–z alphabet, and
you may paste values with 0b, 0o or 0x prefixes,
spaces or underscores — they are ignored. Negative values are supported.
Conversion uses JavaScript BigInt arithmetic, so there is no 32-bit or
64-bit ceiling: a 200-digit decimal number converts to binary exactly, with no rounding
or loss of precision that Number-based converters suffer from. The bit and
byte width of the value is shown underneath, which is handy when picking an integer type
or writing bit masks. Everything runs in your browser — nothing you enter is uploaded.
Frequently asked questions
How do you convert decimal to binary?
Divide the decimal number by 2 repeatedly and read the remainders bottom-up — 255 gives 11111111. This tool does it for you: set the input base to 10, type the number, and the binary result appears instantly alongside octal, hex, base 32 and base 36.
How do I convert hex to decimal?
Multiply each hex digit by its power of 16 and add them up, remembering that a–f mean 10–15. Here you just choose input base 16 and paste the value — 0x, spaces and underscores are ignored, so 0xDEAD_BEEF converts straight to 3735928559.
Can this converter handle very large numbers?
Yes. All conversion uses JavaScript BigInt arithmetic, so there is no 32-bit or 64-bit ceiling and no floating-point rounding: a 30- or 200-digit number converts to any base from 2 to 36 exactly, digit for digit.