YUCTS Tools

UUID Generator and Inspector (bulk UUID v4)

Generate up to 10,000 random version 4 UUIDs at once with crypto.randomUUID(), then copy them or save a TXT file. Paste any UUID to see its version, variant and embedded time.

  • Runs in your browser (no upload)

Generate UUIDs

1–10,000

Letter case

Generating…

Created with the browser's crypto.randomUUID() (crypto.getRandomValues where it is unavailable). 122 bits are random; the other 6 bits encode the version and variant.

Inspect a UUID

Works without hyphens, in uppercase, with { } or with a urn:uuid: prefix.

Result

Canonical form
017f22e2-79b0-7cc3-98c4-dc0c0c07398f
Version
7 (Unix Epoch time-based)
Variant
RFC 9562 (same as OSF DCE / RFC 4122)
Embedded time (UTC)
2022-02-22T19:22:22.000ZThis is whatever the generator wrote; it is not necessarily the real time.

How to use

  1. Enter how many UUIDs you need (1–10,000).
  2. Choose uppercase or lowercase, hyphens and braces.
  3. Use "Copy all" or "Download TXT".
  4. Paste a UUID into "Inspect a UUID" to see its version, variant and time.

FAQ

Can a version 4 UUID ever repeat?

With 122 random bits a collision is extremely unlikely but not impossible: even after generating one billion UUIDs the chance of any duplicate is about 1 in 10^19. Keep a unique constraint in your database anyway.

Is a GUID different from a UUID?

GUID is the name used mainly in Microsoft products; today it normally means the same format as an RFC 9562 UUID.

Can I use a UUID as a password or secret token?

Not recommended. RFC 9562 says UUIDs should not be treated as hard to guess or used as security capabilities. Use a value from a password generator for secrets.

What is the time shown for some UUIDs?

Versions 1 and 6 contain a timestamp in 100-nanosecond steps since 15 October 1582, and version 7 contains Unix time in milliseconds. The value is shown exactly as the generator wrote it, so it is not necessarily the real time.

Are UUIDs stored or sent anywhere?

No. Generation and inspection run in your browser; nothing is sent to a server, saved in the browser or put in the URL.

Notes & limitations

  • What you enter is processed only on this page and is not sent to YUCTS servers.
  • Only version 4 (random) UUIDs are generated. Time-ordered v7 or name-based v5 UUIDs are not generated, although they can be inspected.
  • Up to 10,000 UUIDs per batch.
  • Inspection only decodes the bit layout; it cannot tell whether a UUID was generated correctly or where it is used.

Data sources