UUID Generator
Generate RFC 4122 version 4 (random) UUIDs, one at a time or in bulk — generated entirely in your browser, nothing is ever sent to a server.
Generate a UUID
Generate in bulk
Frequently asked questions
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier, standardized as RFC 4122, formatted as 32 hexadecimal digits in five groups (8-4-4-4-12). It's designed so that two independently generated UUIDs are, for all practical purposes, guaranteed never to collide — useful for database primary keys, distributed systems, file names, and anywhere else you need a unique ID without a central coordinator handing them out.
What is a "version 4" UUID specifically?
RFC 4122 defines several UUID versions based on how they're generated. Version 4 is the random variant: aside from a handful of fixed bits that mark the version and variant, every bit is chosen at random. It's the most common choice today since it needs no coordination or timestamp source, unlike version 1 (timestamp + MAC address) or version 5 (hashed from a namespace and name).
How likely is a UUID collision?
Extremely unlikely. A version 4 UUID has 122 random bits, so you'd need to generate roughly a billion UUIDs every second for about 85 years before the probability of a single collision reached one in a billion. In practice, collisions aren't a realistic concern for this format.
Is it safe to generate UUIDs on this page?
Yes — UUIDs are generated entirely in your browser using the Web Crypto API's
crypto.getRandomValues(), the same cryptographically secure random source used for
things like generating encryption keys. Nothing generated here is transmitted to a server.