UUID Generator
Generate random version 4 UUIDs with your browser's secure random number generator, from one to a thousand at a time. Show them in uppercase, without hyphens or wrapped in braces, copy one or all of them, and paste any UUID into the checker to see whether it is valid. Nothing is sent to a server.
Generated UUIDs
Why This Tool Matters
Unique identifiers are needed long before a system is ready to issue them. A developer seeding a test database wants a few hundred primary keys. A QA engineer filling an API fixture needs distinct request IDs, and a backend engineer wiring up an idempotency key wants one that no other client will pick. Windows work uses the same thing under the name GUID, typically uppercase in braces, which is why those are formatting switches here rather than a separate tool.
The validator covers the other half of the job: a value in a log, a config file or a bug report that is supposed to be a UUID. Paste it and it tells you whether the digits and grouping are right, and which version and variant it declares, including common slips like a missing digit or an extra character. Generation uses crypto.randomUUID() where the browser provides it, and falls back to building a version 4 UUID from secure random bytes.
How to Use
- 01
Set how many
Enter a quantity from 1 to 1,000. The list refreshes as you type, and Regenerate makes a fresh set.
- 02
Pick a format
Switch on uppercase, no hyphens or braces to match what your system expects.
- 03
Copy what you need
Use Copy on a single row, or Copy all for the full list, one UUID per line.
More Text Tools
- Need a checksum for a value? Try the MD5 Hash Generator
- Encoding an ID for a URL or header? Try Base64 Decode & Encode
- Need a readable ID instead? Try the Slug Generator
- Drawing a random winner rather than an ID? Try the Random Name Picker
- Browse all Developer Tools
- Need to change letter case first? Try the full Case Converter
Frequently Asked Questions
What is the difference between UUID v4, v1 and v7?
Version 4 is 122 random bits plus fixed version and variant bits, with no information about when or where it was made. Version 1 combines a timestamp with a machine identifier, which can reveal when and on which machine it was generated. Version 7, standardised in RFC 9562, starts with a millisecond timestamp followed by random bits, so values sort in creation order, which makes it friendlier to database indexes. This tool generates version 4 only.
How likely is a UUID v4 collision?
With 122 random bits there are about 5.3 × 10³⁶ possible values. To reach a 50% chance of a single duplicate you would need to generate around 2.7 × 10¹⁸ of them, which at a billion per second would take roughly 85 years. For any realistic application the risk is far below that of a hardware fault, though it does assume a good random source, which is why this tool uses the browser's secure generator.
Are these UUIDs safe to use as secrets?
They are unpredictable, since they come from the secure random generator, but a UUID is designed to be an identifier, not a credential. If something must stay secret, such as a password reset link, use a purpose-built token with a stated length and expiry. UUIDs are also shown in URLs and logs by habit, so avoid relying on one staying hidden.
Is a UUID the same thing as a GUID?
In practice, yes. GUID is Microsoft's name for the same 128-bit value. Windows tooling usually writes it in uppercase inside braces, such as {3F2504E0-4F89-41D3-9A0C-0305E82C3301}, which you can get by ticking Uppercase and braces.
What does the validator check?
It accepts 32 hexadecimal digits with or without hyphens, optional braces and an optional urn:uuid: prefix, in any case. It then reads the version digit (1 to 8) and the variant bits and reports them. It can tell you the format is right, but not whether the ID is in use anywhere.
Are the generated UUIDs sent or stored anywhere?
No. They are created in your browser and are not uploaded, logged or saved, so every list is gone when you close the tab.