UUID Generator

UUID Generator is a free online tool that creates Universally Unique Identifiers (UUIDs), also known as GUIDs (Globally Unique Identifiers). UUIDs are 128-bit values used to uniquely identify objects, records, and resources in software systems without requiring a central authority.

This generator produces version 4 UUIDs, the random variant, which is the one wanted in almost every case where an id has to be unique without coordinating with anything else. You can generate one at a time or bulk-generate dozens, and copy them in the format your code expects: canonical, uppercase, braced, or with the hyphens removed.

UUIDs are essential in distributed systems, databases, APIs, and microservices where unique identification is needed across different servers and services. Whether you need a primary key for a database record, a session token, or a unique file name, this tool generates standards-compliant UUIDs instantly in your browser.

The versions are not interchangeable, and picking the wrong one has consequences. Version 4 is 122 random bits, which is enough that collisions are not a practical concern: you would need to generate billions before the odds became worth thinking about. Version 1 encodes a timestamp and the machine's network address, so it sorts by creation time and leaks where and when it was made, which is why it fell out of favour. Version 7, the newer option, keeps the time ordering without the hardware identifier, and that ordering matters more than it sounds: random version 4 ids scatter across a database index and fragment it, while time-ordered ids append. The one thing no version is, is secret. A UUID is unique, not unguessable in the sense a security token needs to be, so it should not stand in for one.

You can check the output of this v4 UUID generator by eye. Take an id such as 3f2b8c1e-9d4a-4e7b-b6a2-5c0d8e1f7a93: the first digit of the third group is always 4, the version, and the first digit of the fourth group is always 8, 9, a or b, the variant. Every other hex digit comes from the uuid random generator. Switch Format to No hyphens and the same id is 32 characters; {braces} makes it 38. Any online UUID generator or UUID GUID generator that follows RFC 9562 produces this same layout.