UUID v4 generator

What a version 4 UUID is

A UUID is a 128-bit identifier written as 32 hexadecimal digits in five groups, for example 3b241101-e2bb-4255-8caf-4136c566a962. In version 4, 122 of those bits are random and the rest mark the version and variant. The "4" at the start of the third group tells you it is version 4.

Collisions and security

With 122 random bits, the chance of two UUIDs colliding is negligible: you would need to generate about a billion per second for decades before a duplicate became likely. The values come from crypto.randomUUID(), the browser's cryptographically secure generator. They are unique, but a UUID is an identifier, not a secret; do not use one as a password or API key.

Using them

Choose uppercase if your system expects it (some Microsoft tools show GUIDs in capitals) and "No hyphens" for the compact 32-character form used by some databases and file names. One UUID per line makes the list easy to paste into a spreadsheet, SQL insert or test fixture.

How to use

1. Choose your options.
2. A new result is generated every time you change an option, or click "Generate again".
3. Copy the result or download it.

FAQ

Are these UUIDs sent to a server?

No. They are generated locally with crypto.randomUUID(). Nothing is uploaded or logged.

Is a UUID the same as a GUID?

In practice yes. GUID is Microsoft's name for the same 128-bit format.

Can I generate other versions (v1, v7)?

Not here. This tool produces random version 4 UUIDs only, which cover most uses. If you need time-sortable IDs for database indexes, look for a UUID v7 tool.

Is there a maximum?

You can generate up to 1000 per click. Click "Generate again" for more.