Generate UUIDs in bulk.
Create random v4, time-ordered v7, timestamp v1 or name-based v3 and v5 UUIDs, up to 1,000 at a time, in the format you need. Or check an existing UUID.
Runs in your browserNothing uploaded or storedFree, no sign-up
Your UUIDs
UUIDs0
Version4
Check a UUID
Paste any UUID to see whether it is valid, which version it is and, for v1 and v7, when it was created.
Which version should I pick?
v4 — random
The default choice. 122 random bits make collisions practically impossible. Use it for IDs that should not reveal anything.
v7 — time-ordered
Starts with a millisecond timestamp, so new IDs sort after old ones. This keeps database indexes fast. A great modern default for primary keys.
v5 and v3 — name-based
The same namespace and name always give the same UUID, which is handy for stable IDs derived from a URL or domain. Prefer v5 over v3.
v1 — timestamp
Built from the current time. This version uses a random node ID rather than your MAC address, so it does not leak hardware details.
Questions people ask
What is a UUID?
A UUID (universally unique identifier) is a 128-bit ID written as 32 hex digits in five groups, like 123e4567-e89b-12d3-a456-426614174000. Systems can create them independently without coordinating and still avoid duplicates.
Can two UUIDs ever be the same?
Theoretically yes, but for v4 the chance is so small it is ignored in practice. You would need to generate billions of UUIDs per second for many years before a clash became likely.
What is the difference between a UUID and a GUID?
Nothing important. GUID is Microsoft's name for the same thing. Use the “Wrap in {{ }}” and UPPERCASE options to get the style often seen in .NET and Windows.
Why use UUID v7 instead of v4 for database keys?
Random v4 values land all over a database index, which slows inserts as the table grows. v7 starts with the time, so new rows are added at the end of the index, which is much faster, while staying globally unique.
Are the UUIDs secure and random?
v4, v7 and v1 use your browser's cryptographic random number generator. Even so, a UUID is an identifier, not a secret, so do not use one as a password or access token.
Are the UUIDs sent anywhere?
No. They are generated in your browser and are never uploaded or stored.