How base converter works
A number base (or radix) is the count of unique digits used to represent values. Base 2 uses 0-1, base 10 uses 0-9, base 16 uses 0-9 and a-f, and so on up to base 36 which uses 0-9 and a-z. Converting between bases means parsing the input in its source base to get the underlying value, then re-formatting that value in the target base.
Enter a value, set the source base it is written in, and the target base you want (any integer from 2 to 36). The converter validates every digit against the source base, parses the integer part exactly using arbitrary-precision integers, and converts the fractional part to up to 16 digits in the target base. It also shows the decimal, binary, octal and hexadecimal forms for reference.
Arbitrary-base conversion is common in programming and cryptography: base 32 and base 36 are used for compact identifiers, base 2 and base 16 for low-level bit work, and unusual bases like base 3 or base 60 occasionally appear in algorithms. This tool covers the full 2-36 range that JavaScript digit characters support.
Frequently asked questions
What bases does this converter support?
Any integer base from 2 to 36. That includes the common ones (binary 2, octal 8, decimal 10, hexadecimal 16) plus base 32, base 36, and unusual radices like base 3, base 12, or base 60. Digits above 9 use the letters a-z.
How do I convert decimal to base 36?
Set the source base to 10 (decimal) and the target base to 36, then enter your number. For example, 123456789 in decimal becomes 21i3v9 in base 36. The converter uses arbitrary-precision integers so large values stay exact.
Does it support fractional numbers?
Yes. Enter a value with a decimal point such as 255.5, choose the source base, and the target base. The integer part is converted exactly; the fractional part is converted to up to 16 digits in the target base, which is plenty for almost all real values.
Why was my input rejected?
Every digit must be valid for the source base. The digit 9 is not valid in base 8, and the letter g is not valid in base 16 (it only goes up to f). The converter checks this before parsing and returns a clear error so you can fix the value or the base.
