Number Base Converter
Convert between binary, octal, decimal, hexadecimal and any base from 2 to 36, even for very large numbers.
ConvertersWhy different bases exist
Binary is how computers actually represent numbers, but it is unreadable for a person. Hexadecimal is the compromise: each digit maps exactly to four bits, so conversion is immediate and a byte fits in two characters. That is why colours, memory addresses and error codes are almost always written that way.
Why an ordinary number is not enough
JavaScript numbers lose precision beyond roughly nine quadrillion, and anyone converting to hexadecimal often deals with 64-bit values — identifiers, bit masks, truncated hashes. This tool uses arbitrary-precision integers, so the trailing digits are not silently rounded away.
Bases up to 36
Past 9 the digits run out and letters take over: base 16 uses A to F, base 36 reaches Z. There is no going further, simply because the alphabet ends. High bases are used to shorten numeric identifiers into more compact strings.
Frequently asked questions
Yes. Conversion uses arbitrary-precision integers, so 64-bit values and beyond stay exact down to the last digit.
No, the tool works on integers. Fractions in non-decimal bases are rarely representable exactly, and showing them rounded would mislead more than help.