UUID Generator
Generate universally unique identifiers (UUIDs) instantly for your projects
Generated UUIDs
About UUID Generator
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. UUIDs are standardized by the Open Software Foundation (OSF) as part of the Distributed Computing Environment (DCE).
Version Differences
Version 4 UUIDs are randomly generated, while Version 1 UUIDs are time-based. Version 4 is most common, with a negligible chance of duplicates. Version 1 includes timestamp and MAC address information.
Common Uses
UUIDs are widely used in databases as primary keys, in distributed systems, for session identifiers, and anywhere a unique identifier is needed without central coordination.
Understanding UUIDs in Depth
UUIDs are 36-character strings (32 alphanumeric characters and 4 hyphens) that are unique across both space and time. The probability of a duplicate UUID is so low that it can be considered zero for most practical purposes.
The standard format is 8-4-4-4-12 hexadecimal digits, like this: 123e4567-e89b-12d3-a456-426614174000. Each UUID version has specific characteristics:
- Version 1: Combines time, clock sequence, and node (usually MAC address)
- Version 4: Uses random or pseudo-random numbers
Our tool generates both versions instantly, with the option to create multiple UUIDs at once for batch processing needs.
Frequently Asked Questions
UUID and GUID (Globally Unique Identifier) are essentially the same thing. GUID is Microsoft's implementation of UUID. Both terms are often used interchangeably, though GUID typically refers to Microsoft's variant of UUID.
While not guaranteed to be unique, the probability of a duplicate UUID is extremely low (about 1 in 2.71 quintillion for version 4). For most practical purposes, they can be considered unique, especially when proper generation methods are used.
Use version 4 (random) when you simply need a unique identifier without any embedded information. Use version 1 (time-based) when you need to sort UUIDs chronologically or when you want to extract the creation time from the UUID.
Version 4 UUIDs are random and cannot be predicted if properly generated. Version 1 UUIDs contain the MAC address and timestamp, so parts can be determined if you know when it was generated and the generating machine's network address.
UUIDs should not be used as security tokens since version 1 contains identifiable information and version 4 is random but not cryptographically secure. For security purposes, use proper cryptographic tokens.