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UUID Generator

Random UUIDs, one or many.

Generate

      

    

  


  

    
Validate

    

      

        

      
      
    

  




    
    
    
About the UUID Generator


A UUID (universally unique identifier, RFC 9562, which replaced RFC 4122) is a 128-bit value written as 32 hex digits in five groups, like 550e8400-e29b-41d4-a716-446655440000. This tool generates random version 4 UUIDs in your browser with crypto.randomUUID() (falling back to crypto.getRandomValues()), so they come from a cryptographically secure source and never touch a server.


Generate 1 to 1,000 at a time, format them in uppercase, without hyphens, or wrapped in braces, then copy or download them as a text file. The validator on the right checks one UUID per line and reports its version (v1 to v8, plus the nil and max UUIDs) and variant. It accepts braces, a urn:uuid: prefix and 32-digit hex without hyphens.


How to use it


    

  1. Set the count and press Generate.
    2. 

  2. Pick formatting options; the list updates in place.
    3. 

  3. Copy all or download uuids.txt.
    4. 

  4. To check existing IDs, paste them into Validate, one per line.
    5. 



Examples


Default:     3f2b8c1e-9a4d-4e7b-b1c2-5d6e7f8a9b0c
Uppercase:   3F2B8C1E-9A4D-4E7B-B1C2-5D6E7F8A9B0C
No hyphens:  3f2b8c1e9a4d4e7bb1c25d6e7f8a9b0c
Braces:      {3f2b8c1e-9a4d-4e7b-b1c2-5d6e7f8a9b0c}



Common questions


Can two v4 UUIDs collide?


In practice, no. A v4 UUID has 122 random bits, so you would need to generate around 2.7 x 10^18 of them for a 50% chance of a single duplicate.


How do I tell a UUID's version?


The first digit of the third group is the version: in ...-4e7b-... it is 4. The first digit of the fourth group (8, 9, a or b) marks the standard RFC variant.


Should I use v4 or v7?


v4 is fully random. v7 (RFC 9562) starts with a Unix timestamp in milliseconds, so it sorts by creation time and is friendlier to database indexes. This tool generates v4 and can validate both.