Generate random version 4 UUIDs (GUIDs) in bulk, up to 100 at a time. Choose uppercase, no hyphens or braces, and copy one value, all of them, or a JSON array.
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A UUID generator for random version 4 UUIDs, created with crypto.randomUUID(), up to 100 per click. Windows and .NET call the same identifiers GUIDs, so it works as a GUID generator too.
The output can be shown in uppercase, without hyphens or wrapped in {braces} (the form Windows registry and COM GUID strings use), copied one at a time, all at once, or as a JSON array. Generation happens in your browser, and no value is sent to a server.
A version 4 UUID is 128 bits of which six are fixed - four for the version, two for the variant - and the rest are random. There's no timestamp inside, so the values don't sort by creation time, and each click replaces the previous batch rather than adding to it.
Choose how many UUIDs you need, from 1 to 100.
Click Generate. Each click replaces the previous batch with new random UUIDs.
Switch on Uppercase, No hyphens or {Braces} if your system expects that form.
Copy one UUID, all of them one per line, or the whole batch as a JSON array.
Generate a batch of primary keys, then use Copy All for one per line or Copy as JSON array for a fixtures file.
Request IDs, correlation IDs and mock resource IDs for manual calls from an API client or curl.
Use a UUID as the stored file name, so two uploads called photo.jpg can't overwrite each other.
Real, valid UUIDs to confirm your validator accepts them - including the uppercase, no-hyphen and braced forms if your code should.
Sample Output
7de53e8a-9b63-4f0f-bd81-09f23d884830Structure
8-4-4-4-12 hex groups · 3rd group starts with 4 (version) · 4th group starts with 8/9/a/b (variant)Thirty-two hex digits in groups of 8-4-4-4-12. The 4 at the start of the third group marks version 4, and the 8, 9, a or b at the start of the fourth marks the standard variant. Every other digit is random and changes each time.
Same UUID with Uppercase, No hyphens and {Braces} on
7de53e8a-9b63-4f0f-bd81-09f23d884830Displayed and copied as
{7DE53E8A9B634F0FBD8109F23D884830}The options only change how a UUID is shown and copied; the generated value underneath is the same.
There is no selector for version 1, 5 or 7 UUIDs.
The page doesn't parse or validate a UUID you already have, or read the version out of one.
The count is limited to 1-100, and reloading the page or generating again discards the current batch.
This tool generates version 4. Version 7, defined in RFC 9562, is a newer time-ordered format that is often chosen for database keys.
| Version 4 (generated here) | Version 7 (not generated here) | |
|---|---|---|
| What's inside | 122 random bits | A millisecond timestamp plus random bits |
| Sorts by creation time? | No - random order | Yes - newer values sort after older ones |
| Commonly used for | General identifiers where order doesn't matter | Database primary keys, where time order keeps inserts clustered |
Which should you use?
If you only need a unique identifier, version 4 is fine. If you're choosing a key for a large table and want inserts to stay in order, look at version 7 - you'd need a library or another tool for that, since this page only produces version 4.
Short answers on GUIDs, collisions and using UUIDs as database keys.
No. UUID is the name the standard uses (RFC 9562, which replaced RFC 4122); GUID is Microsoft's name for the same 128-bit identifier. The braced, upper-case form many Windows tools show is just a formatting choice, which the Uppercase and {Braces} options reproduce.
In practice no, but it isn't guaranteed. A version 4 UUID has 122 random bits, which makes an accidental duplicate vanishingly unlikely even across billions of values. Uniqueness is probabilistic and depends on the browser's random number generator; this page uses crypto.randomUUID().
Yes - they're common in distributed systems because any client can create one without asking a central counter, and they don't reveal how many rows exist. The trade-offs are size (16 bytes in binary storage and 36 characters as text, against 4-8 bytes for an integer) and, for random v4 values, scattered inserts into the index; time-ordered UUIDs such as v7 reduce that second cost.
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