Choose how many
From 1 to 1,000 UUIDs at once.
UUID v4 generator
Generate random version 4 UUIDs, one or a thousand at a time, with the format you need. They are created by your browser's secure random generator.
- Free
- No sign-up
- Runs in your browser
100% private — everything is generated in your browser with its secure random number generator, and nothing is sent or stored.
Next step
Keep going with your result in another tool. Nothing is uploaded.
How it works
Pick the format
Add or remove hyphens, use uppercase or wrap them in braces.
Copy or download
Copy the list or download it as a text file.
How to generate a UUID v4
To generate a UUID v4, open this page: version 4 is selected and a batch of random UUIDs is already listed. Change the amount if you need more, choose the format and copy the result. Each one comes from your browser's cryptographically secure random generator, so they are safe to use as identifiers, and none of them is sent anywhere.
What is a UUID v4?
A UUID (universally unique identifier) is a 128-bit value written as 32 hexadecimal digits in five groups, such as f47ac10b-58cc-4372-a567-0e02b2c3d479. In version 4, 122 of those bits are random and 6 are fixed to mark the version and variant. You can spot a v4 by the digit 4 at the start of the third group and by 8, 9, a or b at the start of the fourth.
Anatomy of a v4 UUID
| Part | Value in the example | Meaning |
|---|---|---|
| Group 1 | f47ac10b | random |
| Group 2 | 58cc | random |
| Group 3 | 4372 | starts with 4: version 4 |
| Group 4 | a567 | starts with 8, 9, a or b: variant |
| Group 5 | 0e02b2c3d479 | random |
Can two UUIDs collide?
In theory yes, in practice no. There are about 5.3 × 10^36 possible v4 UUIDs. You would need to generate roughly 2.7 quintillion of them to have a 50% chance of a single duplicate, which is about 86 years at a billion UUIDs per second. That is why systems can create IDs independently, without talking to each other or to a central database.
Good uses and cautions
- Primary keys in distributed databases, order numbers and file names that must never clash.
- Correlation and request IDs for tracing across services.
- Not secrets. A UUID identifies something, it is not a password or a session token that guards access.
- Database indexes. Fully random keys scatter inserts across an index; if that hurts performance, consider version 7.
Private by design
The conversion runs in your browser. What you type, paste or drop is never uploaded, which matters when the text holds tokens, personal data or internal files.
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Frequently asked questions
Are the UUIDs really random?
Yes. They are produced with crypto.getRandomValues, the browser's cryptographically secure generator, not with Math.random.
What is the difference between UUID v4 and v7?
V4 is fully random. V7 starts with a timestamp, so newer ones sort after older ones, which is friendlier to database indexes.
Are UUID and GUID the same?
Yes, for practical purposes. GUID is the name Microsoft uses for the same 128-bit identifier.
Is this converter free?
Yes. There is no sign-up and no limit, and it runs in your browser, so nothing you type is sent to a server.
Does it work on a phone?
Yes. It works in any modern mobile browser, and the result updates as you type.
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