UUID Generator
Generate RFC 4122 version 4 UUIDs (GUIDs) using cryptographic randomness. Bulk generate up to 100 at a time.
How to Use the UUID Generator
- Set the count -- Choose how many UUIDs to generate (1 to 100).
- Choose display options -- Select uppercase or lowercase, and with or without hyphens.
- Generate -- Click the Generate button to create your UUIDs instantly.
- Copy -- Click "Copy All" to copy every UUID to your clipboard, one per line.
About UUIDs
A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit identifier standardized by RFC 4122. The version 4 UUID generated here is created from cryptographically secure random numbers. The format is xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where 4 indicates version 4 and y is constrained to 8, 9, a, or b to indicate the variant.
UUIDs are widely used in software development for database primary keys, distributed systems, session identifiers, and anywhere a unique identifier is needed without central coordination. With 122 bits of randomness, the chance of collision is negligibly small -- you would need to generate over a billion UUIDs per second for decades to have a 50% probability of a single collision.
Frequently Asked Questions
A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. Version 4 UUIDs are generated from random numbers and have an extremely low probability of collision, making them ideal for distributed systems.
UUID and GUID are the same thing. UUID is the standard term (from IETF RFC 4122), while GUID is the name commonly used by Microsoft. They follow the same specification and format.
While theoretically possible, the probability is astronomically small. With 122 random bits, you would need to generate roughly 2.71 quintillion UUIDs to have a 50% chance of one collision. For all practical purposes, every UUID v4 is unique.