Number Base Converter
Enter a number in any base from 2 to 36 and instantly see it converted to binary, octal, decimal, hexadecimal, and a custom base of your choice — arbitrary-precision, so very large numbers convert exactly instead of losing precision.
Binary
Octal
Decimal
Hexadecimal
Custom base
How to use
- Type a number and choose which base it's currently written in.
- Binary, octal, decimal, and hex results update instantly, plus a custom-base result you can set to anything from 2 to 36.
- Click Copy next to any result to copy it.
FAQ
How large a number can this handle?
Arbitrarily large — conversion uses JavaScript's BigInt internally, not the regular Number type, so results stay exact even well beyond the 2^53 safe-integer limit regular floating-point numbers run into.
What characters are valid digits above base 10?
Letters a-z (case-insensitive) extend the digit range past 9 — base 16 uses 0-9 and a-f, base 36 uses the full 0-9 and a-z.
Does it support negative numbers?
Yes — prefix the input with a minus sign; all base conversions carry the sign through.