UUID generator
Create universally unique identifiers (UUIDs or GUIDs) in version 4 or 7, in the format you need, and check whether a UUID is valid and which version it is.
- Free
- No sign-up
- In your browser
Version
122 random bits. The most common choice.
From 1 to 1,000
Result
Validate a UUID
How to use this tool
- Choose the version: v4 if you just need a random identifier, v7 if you want identifiers that sort by creation time.
- Enter how many you want (1 to 1,000) and click “Generate”.
- Adjust the format if needed: uppercase, no hyphens or wrapped in braces (the way Microsoft GUIDs are often shown).
- Copy the result or download it as a .txt file, one UUID per line.
What a UUID is
A UUID (Universally Unique Identifier, also called a GUID in the Microsoft world) is a 128-bit identifier written as 32 hexadecimal digits separated by hyphens in groups of 8-4-4-4-12, for example 919108f7-52d1-4320-9bac-f847db4148a8. Its format is defined in RFC 9562, published in 2024, which replaces the older RFC 4122.
The great advantage of UUIDs is that any system can generate them on its own, without checking a central database, with a chance of collision so low that it's considered negligible in practice. That's why they're used as primary keys, order IDs, file names, and session and message IDs between services.
UUID v4 vs. UUID v7: which to choose
Version 4 is the most widely used: 122 of its 128 bits are random and the remaining 6 indicate the version and variant. It contains no information about when or where it was created.
Version 7, introduced in RFC 9562, starts with the creation date and time in milliseconds (Unix time) and fills the rest with random bits. So v7 UUIDs generated later sort after earlier ones. This is useful as a database primary key, because indexes work better with values that grow in order than with completely random values.
Keep in mind that a v7 UUID reveals when it was created. If that shouldn't be visible (for example, in a public identifier), use version 4.
Can they repeat?
In theory, yes, but with 122 random bits in version 4 the number of possible combinations is so vast that generating two identical ones by chance is extraordinarily unlikely, even when generating billions. In practice, uniqueness failures are usually caused by a faulty random generator, not by chance.
This tool uses the browser's cryptographically secure generator (crypto.randomUUID or crypto.getRandomValues). For v7 UUIDs generated in the same batch, a counter is also used, as RFC 9562 allows, so they stay ordered even when created in the same millisecond.
Examples
A primary key for a new table
Choose v7 and generate one. When you insert rows with v7 UUIDs, new records go to the end of the index, just like with an auto-increment ID.
Test data
Generate 500 v4 UUIDs and download the .txt to import them into a spreadsheet or a test script.
A GUID for Visual Studio or the Windows Registry
Tick “Uppercase” and “Wrapped in braces” to get the format {919108F7-52D1-4320-9BAC-F847DB4148A8}.
Frequently asked questions
What's the difference between a UUID and a GUID?
None in practice. GUID (Globally Unique Identifier) is Microsoft's name for the same kind of 128-bit identifier. They're sometimes shown in uppercase and wrapped in braces, which you can choose in the format options.
How can I tell which version a UUID is?
Look at the first character of the third group: in 919108f7-52d1-4320-9bac-f847db4148a8 it's a 4, so it's a v4 UUID. You can also paste it into the validator on this page, which also shows the creation date if it's a v7.
Can I use a UUID as a password or secret token?
It's not recommended. A v4 UUID is hard to guess, but its purpose is to identify, not to protect: it often shows up in URLs, logs and databases. For secrets, use a password or token generator designed for that.
Are the UUIDs sent to a server?
No. They're generated in your browser and aren't sent to any server or stored. The same goes for any UUID you paste into the validator.
Related tools
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