UUID Generator

UUID Generator

The UUIDs generated by this site conform to RFC 4122 whenever possible.

What is a Version 1 UUID?

A Version 1 UUID is a universally unique identifier that is generated using a timestamp and the MAC address of the computer on which it was generated.

What is a Version 4 UUID?

A Version 4 UUID is a universally unique identifier that is generated using random numbers. The Version 4 UUIDs produced by this site were generated using a secure random number generator.

What is a GUID?

GUID (aka UUID) is an acronym for 'Globally Unique Identifier' (or 'Universally Unique Identifier'). It is a 128-bit integer number used to identify resources. The term GUID is generally used by developers working with Microsoft technologies, while UUID is used everywhere else.

How unique is a GUID?

128-bits is big enough and the generation algorithm is unique enough that if 1,000,000,000 GUIDs per second were generated for 1 year the probability of a duplicate would be only 50%. Or if every human on Earth generated 600,000,000 GUIDs there would only be a 50% probability of a duplicate.

How are GUIDs used?

GUIDs are used in enterprise software development in C#, Java, and C++ as database keys, component identifiers, or just about anywhere else a truly unique identifier is required. GUIDs are also used to identify all interfaces and objects in COM programming.