Free UUID Generator: Random Version 4 IDs

Free tool · nothing is uploaded

Free UUID generator

Create random version 4 UUIDs. Each one is made in your browser from 122 random bits. Blogoose does not receive them, and they are not looked up in a registry.

An example version 4 UUID, with the version digit marked 4 and the variant digit marked 8.
The picture is an example of the shape. The list below is newly generated.

Version 4

New identifiers are created in this browser. They are not sent anywhere.

How a version 4 UUID is built

  1. Sixteen random bytes come from the browser’s cryptographic random source.
  2. The version nibble is set to 4. That is the first character of the third group.
  3. The variant bits are set so the first character of the fourth group is 8, 9, a, or b.
  4. The rest stays random. 122 bits vary. The written form is lowercase hexadecimal with hyphens.
  5. You can make 1 to 20 at a time. Generating again replaces the list. The old IDs are not stored here.

A UUID names a record. It does not prove the record exists, and it is not a password. Two generators can, in principle, produce the same value. With 122 random bits that is rare enough that systems use the value without calling a central registry. This page does not check uniqueness anywhere else.

Questions about this generator

What is a UUID?

A 128-bit identifier written as 36 characters: 8-4-4-4-12 hexadecimal digits with hyphens. A GUID is the same kind of identifier. This page makes version 4, which is random.

What does version 4 mean?

The first character of the third group is 4. That marks the UUID as random rather than time-based. The first character of the fourth group is 8, 9, a, or b. 122 of the 128 bits are random.

Is a UUID a password?

No. It is an identifier. Anyone who can see it can copy it. Do not use it as a password or as a secret token. This page does not check the ID against a registry.

Does this tool upload the IDs?

No. The identifiers are created in the browser. Blogoose does not receive them.