Learn How UUIDs Are Structured

See the version, variant, and time fields that make up a UUID.

Nid oes angen mewngofnodi

UUID or ULID

💡 Versions 1, 6, and 7 (and ULIDs) embed a creation time, which is decoded above. Versions 4 are fully random and carry no timestamp. Everything is parsed in your browser.

learning tips

🎓

Try the built-in examples to see how each UUID version differs in structure.

🧩

The breakdown shows which bits carry the version, variant, timestamp, and node.

📚

A practical way to understand RFC 4122 / RFC 9562 without reading the spec.

🔒

No data is uploaded — experiment freely.

Sut Mae'n Gweithio

Ewch i mewn

Enter your data into the tool above. Everything stays local to your browser.

Proses

The tool processes your data instantly in your browser using JavaScript. No server, no waiting.

Lawrlwythwch

Get your result instantly. Nothing is stored after you leave the page — complete privacy.

Pam defnyddio ein un ni?

✓Hollol rhad ac am ddim - dim costau cudd, byth

✓Nid oes angen cyfrif, e-bost na mewngofnodi

✓Nid yw ffeiliau byth yn gadael eich dyfais

✓Dim cyfyngiadau maint ffeil o gwbl

✓Dim dyfrnodau ar unrhyw allbwn

Also check out…

🏷️

Check a UUID Version

Find out whether a UUID is v1, v4, v7, or another

🕒

Extract the Timestamp from a UUIDv7

Decode the creation time embedded in a sortable UU

🆔

Decode a ULID

Read the timestamp and randomness from a ULID.

🐞

Debug IDs in Logs and Databases

Quickly understand an unfamiliar identifier you fo

Cwestiynau Cyffredin

Back to UUID Inspector