Base Converter
Convert numbers between any bases (2-36)
Common Bases
Custom Base
About the Base Converter
This base converter handles any base from 2 to 36, not just the common four. Enter a value in one base and read it in all the others, with digits beyond 9 represented by letters as the convention requires.
A base converter changes how a number is written without changing its value. Base 2 uses two digits, base 16 uses sixteen, and once past base 10 the extra digits are letters — so base 36 runs 0 to 9 then A to Z, which is why it is used for compact identifiers.
The unusual bases have real uses. Base 32 encodes binary data using only unambiguous characters, which is why TOTP secrets and some file identifiers use it. Base 36 produces the shortest alphanumeric representation of a number, common in URL shorteners and short IDs.
For the everyday programming cases — binary, octal, decimal and hex — the number base converter is more direct. Use this one when a base outside that set is involved.
How to use the Base Converter
- Enter your value. Type the number as written in its current base.
- Set the input base. Choose the base the value is currently in.
- Choose the output base. Pick any base from 2 to 36.
- Copy the result. Take the converted value.
Base Converter features
- Any base from 2 to 36
- One-tap presets for binary, octal, decimal, hex, base 32 and base 36
- Every other base shown at once
- Negative values supported
- Digits beyond 9 shown as letters, per convention
- Copy any result
Frequently asked questions
Which bases are supported?
Every base from 2 to 36, with presets for the common ones. The upper limit is 36 because that is where the digits run out — ten numerals plus twenty-six letters.
Why do bases above 10 use letters?
Because a single symbol is needed per digit value. Hexadecimal needs sixteen, so A to F stand for 10 to 15. The same convention continues upward, which is how base 36 uses the whole alphabet.
Can it convert fractions?
No, whole numbers only. A value with a decimal point will not convert — fractional conversion in an arbitrary base is a different problem, and most fractions do not terminate in most bases.
What are the uncommon bases actually for?
Base 32 and base 36 are used to make identifiers shorter — a long number becomes a compact alphanumeric string, which is where short URLs and some database keys come from. Base 3 and base 7 mostly turn up in coursework.