Which UUID version should I use?

Use version 4 when you just need a random unique ID. Use version 7 when IDs are database keys and you want them to sort by creation time. Use version 5 when the same input must always give the same ID.

Can two UUIDs be the same?

In practice no. A version 4 UUID has 122 random bits, so you would have to generate billions per second for many years before a collision became likely.

Are these UUIDs generated securely?

Yes. They are made in your browser with its cryptographically secure random number generator, and nothing is sent to a server.

What is the difference between a UUID and a GUID?

They are the same thing. GUID is the name Microsoft uses, and the format is identical. GUIDs are often written in uppercase and sometimes wrapped in braces, which the Validate tab accepts.

UUID Generator

Generate UUID v4 and v7 in bulk, and validate any UUID.

Runs in your browser. Nothing is uploaded.

Remember my last input

What is UUID Generator?

A UUID, or universally unique identifier, is a 128-bit value written as 32 hexadecimal digits in five groups, for example 550e8400-e29b-41d4-a716-446655440000. Developers use UUIDs as database keys, request and correlation IDs, file names and API identifiers because they can be created anywhere, without a central server handing out numbers, and the chance of two being the same is vanishingly small.

This UUID generator creates the versions developers actually need. Version 4 is completely random and is the usual default. Version 7 puts a millisecond timestamp first, so new IDs sort in creation order, which makes them much friendlier to database indexes. Version 1 combines the time with a node value, and version 5 builds a repeatable UUID from a namespace and a name, so the same input always produces the same ID. You can generate up to 1,000 at once, switch to uppercase, remove the hyphens, wrap them in quotes, and copy them as lines, a comma-separated list or a JSON array.

The Validate tab checks UUIDs for you. Paste one or a whole list and it tells you whether each is valid, which version and variant it is, and the creation time stored inside version 1, 6 and 7 UUIDs. It accepts braces, a urn:uuid: prefix and 32 digits without hyphens, and tells you what it cleaned. Random values come from your browser, nothing is uploaded, and nothing you enter leaves your device.

How to use

Choose the UUID version. Version 4 is a good default, and version 7 is best when you want IDs that sort by time.
Set how many you need, from 1 to 1,000. The current UUIDs stay the same when you change the count or the formatting.
Pick uppercase, hyphens, quotes or an output style such as a JSON array, then click Generate new for a fresh batch.
Use Copy all or Download .txt to take the list with you.
To check existing UUIDs, open the Validate tab and paste one or many.

Example

Input

Version 4, count 2

Output

3f8c1a52-7d94-4b6e-9a0c-5e2d7b8a1f34
9b2e4c7a-1d63-4f08-8c5b-a3e6d0f21b97

Frequently asked questions

Which UUID version should I use?: Use version 4 when you just need a random unique ID. Use version 7 when IDs are database keys and you want them to sort by creation time. Use version 5 when the same input must always give the same ID.
Can two UUIDs be the same?: In practice no. A version 4 UUID has 122 random bits, so you would have to generate billions per second for many years before a collision became likely.
Are these UUIDs generated securely?: Yes. They are made in your browser with its cryptographically secure random number generator, and nothing is sent to a server.
What is the difference between a UUID and a GUID?: They are the same thing. GUID is the name Microsoft uses, and the format is identical. GUIDs are often written in uppercase and sometimes wrapped in braces, which the Validate tab accepts.