How to use
- Set the length with the slider. The default is 21 characters.
- Choose how many. They are generated straight away; click Generate for a new batch.
- Copy the list or download it as a text file.
Options explained
- Alphabet
- 64 URL-safe characters — A–Z, a–z, 0–9, underscore and hyphen. Each character carries 6 random bits.
- Length
- 6 to 64 characters. The default 21 characters hold 126 random bits, about as collision-resistant as UUID v4 (122 bits).
- Collision estimate
- Shown under the list — how many IDs of the current length you can generate before there is a 1% chance of any duplicate.
Example
V1StGXR8_Z5jdHi6B-myTThe default length is 21 characters.
Frequently asked questions
What length should I use?
For globally unique IDs, keep the default 21 characters — about 1.31 × 10¹⁸ IDs before a 1% chance of a duplicate. For IDs used only in a small scope, such as elements on one page, 8–12 characters is enough; 10 characters reach a 1% chance after about 152 million IDs.
Why use Nano ID instead of UUID?
It is shorter for the same randomness (21 characters versus 36) and every character is URL-safe, so nothing needs escaping. The trade-off is that there is no format standard and databases have no native type for it.
Can I use it for tokens or password-reset links?
Yes. Characters are picked with crypto.getRandomValues, which is unpredictable, without modulo bias. Use at least 22 characters (132 bits) for tokens.
Is anything uploaded?
No. IDs are generated in your browser and never sent to a server.
Privacy
This tool runs entirely in your browser. Your files and text are processed on your device and are never uploaded to our servers.