UUID / GUID Generator
Generate version-4 Universally Unique Identifiers (UUIDs) and Globally Unique Identifiers (GUIDs) instantly for databases, APIs, and distributed systems.
What Is a Version-4 UUID and How Does It Work?
The Mathematics of Zero Collisions
A Version-4 UUID contains 128 bits of data, with 122 bits generated from pure cryptographic randomness. There are 2^122 (approximately 5.3 undecillion or 5.3 × 10^36) possible unique values.
To have a 50% probability of generating just one collision, you would need to generate 1 billion UUIDs every single second for approximately 85 years. This makes UUID v4 safe for distributed database primary keys, session tokens, and file IDs without needing a centralized coordinating server.
UUID vs. GUID: Is There Any Difference?
UUID (Universally Unique Identifier) is the open IETF standard (RFC 4122). GUID (Globally Unique Identifier) is Microsoft's implementation of the identical standard, traditionally formatted with enclosing braces and uppercase letters in COM and Windows APIs (e.g. {25B8C0D4-6D29-4F42-83AA-7C6933F89001}). Mechanically, they are interchangeable.