Number Base Converter
Convert numbers between binary, octal, decimal, hexadecimal and any base 2-36
Custom base
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Convert any number between binary, octal, decimal, hexadecimal and arbitrary bases from 2 to 36. All four standard bases are kept in sync as you edit any field. Useful for low-level programming, CTF challenges and computer science homework.
How to convert number bases
1
Enter a number
Type a value in any of the four fields (bin, oct, dec, hex).
2
See sync results
Other bases update instantly to show the equivalent value.
3
Use custom base
Pick a custom base (2-36) for non-standard conversions.
All standard bases
Binary, octal, decimal and hexadecimal kept in sync.
Custom base 2-36
Convert to and from any base between 2 and 36.
Big number safe
Uses BigInt under the hood - handles numbers far beyond 2^53.
Copy any base
One-click copy for every result.
FAQ
Base 2 uses two digits (0 and 1) and is how all digital electronics represent numbers internally.
Base 16 uses 0-9 and A-F. Compact for representing bytes - every byte fits in two hex digits.
Yes. Negative integers are converted using a leading minus sign.
Currently only integers. Floating-point base conversion is not standard and varies by use case.
Base 36 (digits 0-9 and letters A-Z) is the max supported by the underlying JavaScript parseInt and toString.