UUID Generator

This tool generates UUIDs — 128-bit identifiers formatted as 32 hexadecimal characters in the standard 8-4-4-4-12 pattern. Version 4 UUIDs are randomly generated, which is why they are the default choice for most applications.

You choose how many to generate (one by default, more if you need a batch), and each run produces fresh random identifiers you can copy.

The key property of a UUID is practical uniqueness: with 122 bits of randomness, the chance of two generated UUIDs colliding is vanishingly small — small enough that systems treat them as unique without coordination.

Each UUID is produced by the browser's crypto.randomUUID() function, which uses a cryptographically secure random source — the same kind of randomness behind TLS encryption.

The function builds the identifier's 128 bits from random data, sets the version and variant bits that mark it as a v4 UUID, and formats the result in the standard hyphenated form.

Everything runs locally. No request is made to any server, so the identifiers are generated on your device and nothing is stored.

A UUID is a 128-bit identifier. Version 4 UUIDs are built from random bits: 122 of the 128 bits are random, while 6 bits are fixed to mark the version (4) and the variant. The standard textual form is 36 characters: 32 hex digits in five groups separated by hyphens.

The uniqueness guarantee is probabilistic, not absolute. With 122 random bits, generating a billion UUIDs per second for 86 years gives roughly a 50% chance of one collision across the entire run — a level of safety that makes collisions practically impossible in real systems.

Because v4 UUIDs carry no information about when or where they were created (unlike some other UUID versions), they are the safe default when you simply need a unique identifier.