UUID Generator

Generate random version 4 or time-ordered version 7 UUIDs, up to 1,000 at a time.

Result

Choose your options and select Generate.

Runs in your browser — nothing you enter is sent to a server.

How the UUID Generator works

A UUID (universally unique identifier, also called a GUID) is a 128-bit number written as 32 hexadecimal digits, like 3f2b8c1e-9d4a-4e6f-b1c2-7a8d9e0f1a2b. Choose a version, how many you need and the format, then select Generate UUIDs.

UUIDs are made in your browser with its cryptographically secure random generator (crypto.getRandomValues) and follow RFC 9562: the digit after the second hyphen is the version (4 or 7), and the first digit of the fourth group is 8, 9, a or b (the variant).

Formula

p ≈ n² ÷ (2 × 2¹²²)

Where:

n: Number of random (version 4) UUIDs

Version 4 has 122 random bits. Even after generating a billion UUIDs, the chance that any two match is about 1 in 10¹⁹.

Examples

Version 4

9b2e4f7a-3c1d-4a8e-9f0b-6d5c4b3a2e1f — all random except the version (4) and variant (9).

Version 7

019995a1-6c00-7d3e-a8b2-4f6e1c9d0b7a — the first 12 digits are the time in milliseconds since 1970, so newer UUIDs sort after older ones.

Frequently asked questions

Should I use version 4 or version 7?

Version 4 for general IDs that reveal nothing. Version 7 for database primary keys: because it grows over time, new rows go at the end of the index, which is faster than scattering random keys. It does reveal when the ID was created.

Are UUIDs secure tokens?

They're unique, not secret. Don't use them as passwords or session keys; use the Random String Generator or Password Generator for secrets.

Is a GUID the same as a UUID?

Yes. GUID is Microsoft's name for the same format; it's often written in uppercase with braces, which the format options produce.