UUID generator

Get random v4 or time-ordered v7 UUIDs, one at a time or in bulk.

What it does

A UUID is a 128-bit identifier you can create anywhere without asking a central server, with practically no chance of two being the same. Version 4 is fully random. Version 7, standardised in 2024 (RFC 9562), starts with the current time, so new IDs sort in creation order, which keeps database indexes compact and fast. UUIDs here are made with your browser’s cryptographically secure random generator, and v7 values made in the same millisecond still come out in order. You can also paste any UUID to see its version and, for v1 and v7, the moment it was created.

How to use it

How it works

A new version 4 UUID is ready as soon as the page opens. Click “Copy” to use it.
Need more? Choose v4 or v7, enter how many (up to 1000) and click “Generate”. Uppercase, hyphens and braces can be switched on or off.
Copy them all, or download them as a text file with one UUID per line.
To check an existing UUID, paste it under “Check a UUID” to see its version and, for v1 and v7, when it was created.

Common uses

Creating primary keys or test fixtures for a database
Generating IDs for API requests, idempotency keys or correlation IDs
Finding out when a v7 or v1 UUID from a log or database was created

Tips

Prefer v7 for database primary keys: random v4 keys land all over the index and slow down inserts on large tables.
A v7 UUID reveals when it was created. Use v4 where that time shouldn’t be visible, such as public share links.
Store UUIDs in a native uuid or 16-byte binary column rather than as 36-character text; it’s less than half the size.

Questions

Can two UUIDs ever be the same?

In theory yes, in practice no. A v4 UUID has 122 random bits; you would need to generate a billion per second for about 86 years to reach a 50% chance of a single duplicate.

What’s the difference between v4 and v7?

v4 is entirely random. v7 starts with a millisecond timestamp followed by random bits, so v7 IDs sort by creation time while staying unique and hard to guess.

Are these UUIDs safe to use as secret tokens?

They’re made with a cryptographically secure generator, but UUIDs aren’t designed as secrets, and v7 shows its creation time. For passwords or API keys, use a dedicated token generator with more randomness.

Is a GUID the same as a UUID?

Yes. GUID is Microsoft’s name for the same 128-bit format. Some Microsoft tools write it in uppercase or inside braces, which you can switch on here.

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