Online Tool Store
UUID Version Detector
Detect a UUID's version and variant, and read what that version implies about ordering, uniqueness, and embedded timestamps.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Developer
UUID Version Detector
Frontend preview — no upload or external service.
Detection result
Version 7, RFC 4122 variant. Embedded Unix timestamp decodes to 2026-08-19T09:14:22Z, so this identifier sorts chronologically.
How the UUID Version Detector works
- Paste the UUID, with or without hyphens.
- Read the version digit — it is the first character of the third group.
- If it is version 1 or 7, the decoded timestamp tells you when it was generated, which is sometimes information you did not intend to publish.
The method
The version is encoded in a fixed position: the first hex digit of the third group. The variant sits in the first bits of the fourth group.
xxxxxxxx-xxxx-Vxxx-Nxxx-xxxxxxxxxxxx — V is the version, N encodes the variant
Version 4 is random, version 7 is time-ordered, version 1 embeds a timestamp and historically a MAC address.
FAQ
Which UUID version should I use?
Version 4 for pure randomness with no ordering. Version 7 when you want random-looking identifiers that also sort by creation time — which is much kinder to database indexes.
Why does version 7 help database performance?
Because random v4 keys scatter inserts across a B-tree index, fragmenting it. Time-ordered v7 keys append near the end, which keeps inserts localised.
Do UUIDs leak information?
Version 1 embeds a timestamp and, in older implementations, the generating machine's MAC address. Version 7 embeds a timestamp deliberately. Version 4 leaks nothing beyond its randomness quality.
How we compare
| Feature | Online Tool Store | A CLI script | An IDE plugin |
|---|---|---|---|
| Decodes embedded timestamps | ✓ | ✗ | ✓ |
| Explains variant bits | ✓ | ✗ | Sometimes |
| Nothing transmitted | ✓ | ✓ | ✗ |
| No install | ✓ | ✗ | ✓ |
UUID Version Detector reads the version and decodes what it implies — including timestamps that a v1 or v7 identifier publishes whether you meant it to or not.