UUID Generator (v4, v7)

How to use

1. Choose the Version: v4 (random) or v7 (time-ordered).
2. Enter the Count, 1–100. Changing the version or count creates a new set.
3. Pick a format with Uppercase, No hyphens and { } braces. The options can be combined and apply to the current list without generating new UUIDs.
4. Press Copy all to copy the whole list, one UUID per line.
5. Press ↻ Regenerate for a new set with the same settings.

Frequently asked questions

What is the difference between v4 and v7?

v4 is 122 random bits. v7 (RFC 9562) starts with the creation time as a 48-bit Unix timestamp in milliseconds followed by 74 random bits, so values sort in the order they were made, which keeps database indexes compact; note that a v7 UUID reveals when it was created.

Can two UUIDs ever be the same?

In practice, no. With 122 random bits you would need about 2.7 × 10^18 v4 UUIDs for even a 50% chance of a single duplicate; v7 UUIDs made in the same millisecond still each have 74 random bits, so a clash is just as unlikely.

Are v7 UUIDs from one batch in order?

Yes. Within a batch each UUID’s timestamp is 1 ms later than the previous one, so the list sorts in the order shown even though it was generated within the same millisecond. The last values in a large batch therefore carry a time up to 99 ms ahead.

Which format should I use?

The standard form is 36 characters: lowercase hex with hyphens in 8-4-4-4-12 groups. No hyphens gives 32 hex characters, and braces give the Windows GUID style; uppercase and lowercase are the same value.

Are the UUIDs created on a server?

No. They are generated in your browser with its secure random number generator (crypto.randomUUID for v4, crypto.getRandomValues for v7), and the UUIDs are not sent to our server.