UUID Generator
Generate unique identifiers (UUIDs, also called GUIDs) in version 4 or the newer time-ordered version 7, and check any UUID you paste. Generated securely in your browser.
Fully random. The most widely used version.
Validate a UUID
How to generate UUIDs
Choose the version: v4 for fully random IDs, or v7 if you want IDs that sort by creation time.
Pick how many you need and the format: uppercase or lowercase, with or without hyphens.
Copy a single UUID, copy the whole list or download it as a text file. Press Generate new for a fresh set.
Common uses
Database primary keys
UUIDs can be created anywhere without asking the database for the next number. Version 7 keeps indexes efficient because new keys arrive in order.
Distributed systems
Different servers, apps or devices can generate IDs independently with no realistic risk of collision.
Files and uploads
Naming files with a UUID avoids clashes and doesn't reveal how many files exist, unlike 1, 2, 3…
Test data
Developers generate batches of UUIDs to fill fixtures, mocks and sample records.
How UUIDs are generated here
A UUID is a 128-bit number written as 32 hexadecimal digits in five groups, such as 123e4567-e89b-12d3-a456-426614174000. A few bits record the version and the variant; the rest carry the actual identifier.
Version 4 fills 122 bits with random data from your browser's cryptographic generator. There are so many possible values (about 5.3 × 10³⁶) that two random UUIDs colliding is not a practical concern. Version 7, standardized in RFC 9562, starts with the current Unix time in milliseconds and fills the rest with random bits, so UUIDs created later sort after earlier ones.
The validator accepts UUIDs with or without hyphens, in braces or with the urn:uuid: prefix, and shows the version, the variant and, for version 7, the moment it was created. UUIDs are generated on your device and never sent anywhere.
Frequently asked questions
Is a UUID the same as a GUID?
Yes. GUID (globally unique identifier) is the name Microsoft uses for the same 128-bit format. Older Microsoft GUIDs may use a different variant, which the validator shows.
Should I use version 4 or version 7?
Use v7 for database keys and anything you sort, because new IDs follow older ones and keep indexes compact. Use v4 when the ID shouldn't reveal when it was created.
Can two UUIDs ever be the same?
In theory, yes; in practice, no. With v4 you would need to generate billions of UUIDs every second for many years to have a meaningful chance of a single duplicate.
Are these UUIDs secure enough for tokens?
They come from a cryptographic random generator, but a UUID is an identifier, not a secret. For session tokens or API keys, use a dedicated random token generator.
Does version 7 reveal anything?
Yes, its first digits encode the creation time to the millisecond. The validator decodes it, which is useful for debugging but worth knowing if the timing is sensitive.