Which UUID version should I choose?
Use v5 for deterministic name-based IDs, v4 for random IDs, v7 for time-ordered IDs, or v3 when MD5 interoperability is required.
Generated UUIDs
Results appear only after generation.
No UUIDs generated yet.
How to generate UUIDs
- Choose UUID v3, v4, v5, or v7. UUID v5 is selected by default.
- For v3 or v5, choose a namespace and enter one exact name per line.
- For v4 or v7, choose a quantity from 1 to 100.
- Generate the values, then copy one UUID or the complete list.
Version behavior
UUID v3 combines a namespace and UTF-8 name with MD5 for interoperability. UUID v5 uses SHA-1 and is the preferred name-based option offered here for new workflows. Both are deterministic and preserve exact names without trimming or Unicode normalization.
UUID v4 uses secure browser randomness. UUID v7 combines a millisecond Unix timestamp with secure randomness and keeps values increasing within this page's generator instance, including same-millisecond batches and clock rollback.
Practical examples
With the DNS namespace, the name www.example.com produces 2ed6657d-e927-568b-95e1-2665a8aea6a2 in UUID v5 and 5df41881-3aed-3515-88a7-2f4a814cf09e in UUID v3.
UUID v7 values sort by their embedded generation time, while v4 values do not carry ordering information.
Privacy and technical limits
Your input and results are processed in this browser and are not uploaded by this tool. Names, namespaces, UUIDs, quantities, and generation history are not persisted.
UUID v7 exposes generation-time information. Ordering is limited to this generator instance and is not promised across tabs, devices, reloads, or independent systems. Secure random generation must be available for v4 and v7.
Frequently asked questions
Why can UUID v3 or v5 repeat?
The same exact namespace and name intentionally produce the same deterministic UUID. Case and whitespace are significant.
Are UUIDs passwords or guaranteed unique database constraints?
No. UUIDs are identifiers, not secrets, encryption, or a replacement for enforcing constraints in your own system.
Can this tool check my database for a collision?
No. Generation runs locally and cannot inspect records in your application or database.
Related tools
Explore another available JustRandom tool that may help with a related task.