Nano ID generator
Creates ids the Nano ID way: 21 characters by default from a 64-symbol URL-safe alphabet, or a custom alphabet and length.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter length, alphabet, custom alphabet (when selected) and how many.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Each character comes from a secure random byte masked to the nearest power of two; bytes beyond the alphabet size are rejected so the distribution stays uniform. Entropy = length × log2(alphabet size) bits.
Example
Inputs: Length = 21, Alphabet = URL-safe A-Z a-z 0-9 _ - (64), Custom alphabet (when selected) = ABCDEFGHJKLMNPQRSTUVWXYZ23456789, How many = 5. Result: IDs: 11IY0uOes4v0mIsxsKEZB hrLCuDOq07mPrWrry_pbm hGu1LgXJ0IEKBhAYgY-2O BJ0P4xeRKqP-t6rF3LI4e XUp-V9kFGWGO6o4-83qhP; Length of each id: 21 symbols; Alphabet size: 64.
ABCDEFGHJKLMNPQRSTUVWXYZ23456789
11IY0uOes4v0mIsxsKEZB hrLCuDOq07mPrWrry_pbm hGu1LgXJ0IEKBhAYgY-2O BJ0P4xeRKqP-t6rF3LI4e XUp-V9kFGWGO6o4-83qhP
Limits and caveats
- The ids are random and change on every recalculation, so copy them before changing options.
- Short lengths raise the collision risk quickly; keep around 120 bits of entropy for public ids.
Questions about this tool
Is a Nano ID shorter than a UUID for the same security?
Roughly yes: the default 21 symbols carry 126 random bits, against 122 bits in a 36-character UUID v4.
Why are some random bytes rejected?
Taking a plain remainder makes some symbols more common than others; rejection keeps every symbol equally likely.
Can a custom alphabet use Arabic letters?
Yes, each letter counts as one symbol, but URLs will then be percent-encoded and become longer.