UUID / GUID Generator

Generate RFC 4122 version 4 UUIDs with secure randomness. Create one identifier or a batch of up to 20 — all in your browser.

Quantity (1–20)

UUIDClick generate

How to use the UUID generator

Set the quantity — any number from 1 to 20 — using the number field.
Click Generate to create that many version 4 UUIDs.
The UUIDs appear one per line in the result block, ready to copy.
Paste them into your database records, test data, or code where a unique identifier is required.

What a UUID is

A UUID (Universally Unique Identifier) — also called a GUID (Globally Unique Identifier) — is a 128-bit value written as 32 hexadecimal digits grouped into five parts separated by hyphens, like 550e8400-e29b-41d4-a716-446655440000. The format is defined by RFC 4122, and the sheer size of the number space means two correctly generated UUIDs are effectively guaranteed never to collide.

Why version 4

There are several UUID versions, each with a different way of producing the value. Version 4 is the random one: 122 of the 128 bits come from a random source, while a few fixed bits mark the version and variant so the UUID is self-describing. Because the value is random rather than derived from a timestamp or machine address, it reveals nothing about where or when it was generated. That makes version 4 the right choice for primary keys, session tokens and test fixtures.

This tool builds each UUID with the browser's cryptographic random generator, crypto.getRandomValues, then sets the version and variant bits exactly as the RFC requires. The result is a standards-compliant identifier that any UUID-aware library will recognise.

Reading the UUID format

The five hyphen-separated groups have a fixed structure. The third group always begins with a 4, which is what tells any library that this is a version 4 UUID. The first character of the fourth group is restricted to a small set of values — 8, 9, a or b — that mark the RFC 4122 variant. You can spot a correctly generated identifier at a glance by checking those two positions.

Where developers use UUIDs

Primary keys in databases where records may be created across multiple servers.
Unique names for uploaded files, avoiding filename collisions.
ID tokens in URLs and API requests that must be hard to guess.
Seed data and test fixtures that need many distinct identifiers quickly.

Frequently asked questions

No. They are generated locally in your browser using secure cryptographic randomness. Nothing is uploaded or stored.

In practice, no. The random version 4 space is so large that the chance of a collision is negligible for any realistic number of identifiers.

They are the same thing. GUID is Microsoft's name for the same 128-bit identifier that the rest of the industry calls a UUID.

Yes, completely free with no signup and no limits.