Developer
UUID Generator
Generate random version 4 UUIDs, or time-sortable version 7 UUIDs, one at a time or up to 500 at once. Paste a UUID to check its version.
5 UUIDs (v4)
Download .txtv4 or v7?
- v4 is 122 random bits: the usual choice for IDs, tokens and keys.
- v7 starts with the time in milliseconds, so new IDs sort after old ones. Databases index them faster than v4.
- Both are made with a cryptographically secure random generator and are new on every load. Nothing is stored.
UUID Generator: frequently asked questions
What is a UUID?
A UUID (universally unique identifier), also called a GUID, is a 128-bit ID written as 32 hex digits, like 3f2b8c1e-9a4d-4e6f-8b2a-1c7d5e9f0a3b. It is unique without needing a central register.
Should I use UUID v4 or v7?
v4 is fully random and the usual choice. v7 starts with a timestamp, so IDs sort in creation order, which makes database indexes faster. Both are safe to use as primary keys.
Can two generated UUIDs be the same?
In practice, no. A v4 UUID has 122 random bits; you would need to make billions every second for many years before a repeat became likely.
Are the UUIDs stored?
No. They are made with a cryptographically secure random generator when the page loads and are never saved.