UUID Generator & Validator
Generate random (v4), time-ordered (v7 or v1), or name-based (v3/v5) unique identifiers — or paste an existing UUID to validate it and decode its version, variant, and embedded timestamp.
Name-Based (v3 / v5)
Validate / Decode
How to use it
v7 and v1 encode a timestamp so they sort roughly by creation order — v7 is the modern, recommended choice (RFC 9562). v4 is fully random. v3/v5 are deterministic: the same namespace + name always produces the same UUID, which is useful for generating stable IDs from external identifiers like a URL or domain name. Paste any UUID into the validator to check its format and decode its version/variant/timestamp.
Frequently Asked Questions
Which version should I use?
Default to v7 for new systems — it's unpredictable enough for most needs while sorting by creation time, which is friendlier to database indexes than v4. Use v4 when you specifically don't want any information (including approximate creation time) encoded. Use v3/v5 when you need the same input to always produce the same UUID.
v3 vs v5 — which one?
They're the same algorithm with different hashes: v3 uses MD5, v5 uses SHA-1. Prefer v5 — MD5 is kept only for backward compatibility with older v3 UUIDs.
Are generated UUIDs guaranteed to be unique?
In practice, yes — for v4/v7 the probability of a random collision is statistically negligible.