UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit value written as 32 hexadecimal digits in five hyphen-separated groups, like 550e8400-e29b-41d4-a716-446655440000. Microsoft calls them GUIDs — same thing. They let independent systems create identifiers without coordinating with each other.

A version 4 UUID is generated from random data: 122 of its 128 bits are random, and the rest mark the version and variant. This generator uses your browser’s cryptographically secure random source, the standard choice for database keys, session ids and general-purpose identifiers.

In theory yes, in practice no. With 122 random bits there are about 5.3 undecillion (5.3 × 10³⁶) possible v4 UUIDs. You would need to generate roughly a billion UUIDs per second for about 85 years to reach even a 50% chance of a single collision, which is why systems treat them as unique.

Nothing meaningful — GUID (Globally Unique Identifier) is Microsoft’s name for the same 128-bit standard. GUIDs in Windows are often written in uppercase inside braces, like {550E8400-E29B-41D4-A716-446655440000}; this generator has options for both.

Yes. It is completely free with no sign-up, and every UUID is generated locally in your browser using crypto.randomUUID — a cryptographically secure source. Nothing is fetched from or sent to any server, and the tool works offline once the page has loaded.