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UUID Version Detector

Paste a list of UUIDs to learn which version each one is, what it encodes and when the time-based ones were created.

Processed locally in your browser

Options
{braces}, urn:uuid: and 32-hex forms are accepted. Separate values with new lines, spaces or commas.0 chars · 0 lines
The result will appear here.

What is UUID Version Detector?

The version of a UUID is the first hex digit of its third group, and the variant is set by the top bits of its fourth group. From those two fields you can tell whether an ID is random (v4), name-based (v3, v5), time-based (v1, v6, v7), or a legacy GUID from another scheme.

This tool decodes each value in your list: version and its meaning, variant, the embedded UTC timestamp of v1, v6 and v7, the clock sequence and node of v1 and v6, the domain and local ID of v2, and the special NIL and MAX values. A summary counts each version and shows the earliest and latest timestamp found.

How does it work?

  1. Paste one UUID per line; braces, urn:uuid: prefixes and 32-digit forms without hyphens are accepted.
  2. Optionally add a Unix-milliseconds column for the time-based versions.
  3. Read the summary for the count per version and the time range, then scan the table row by row.
  4. Copy the CSV result or download it as uuid-versions.csv.

Common use cases

  • Auditing a database column to see whether keys are v4 or v7 before choosing an index strategy.
  • Finding out when a v1 or v7 identifier was created, for example while debugging a log line.
  • Spotting NIL UUIDs (all zeros) that indicate a missing value in exported data.
  • Recognising legacy Microsoft GUIDs that do not follow the RFC variant.

Examples

Try this input in the tool above:

Input
550e8400-e29b-41d4-a716-446655440000
018f3f4e-0d3f-7cc2-8a1e-5b2d9c4a7e10
6ba7b810-9dad-11d1-80b4-00c04fd430c8
1ee1a5f0-6b3c-6fb0-b3c9-0242ac120002
886313e1-3b8a-5372-9b90-0c9aee199e5d
00000000-0000-0000-0000-000000000000
ffffffff-ffff-ffff-ffff-ffffffffffff
Output
line,uuid,version,variant,timestamp_utc,unix_ms,detail
1,550e8400-e29b-41d4-a716-446655440000,4,rfc,,,purely random; nothing can be decoded
2,018f3f4e-0d3f-7cc2-8a1e-5b2d9c4a7e10,7,rfc,2024-05-03T16:33:50.911Z,1714754030911,timestamp = first 48 bits (ms); the rest is counter/random
3,6ba7b810-9dad-11d1-80b4-00c04fd430c8,1,rfc,1998-02-04T22:13:53.1511824Z,886630433151,clock seq 180; node 00:c0:4f:d4:30:c8 (MAC-like)
4,1ee1a5f0-6b3c-6fb0-b3c9-0242ac120002,6,rfc,2023-07-04T11:36:33.1726768Z,1688470593172,clock seq 13257; node 02:42:ac:12:00:02 (MAC-like)
5,886313e1-3b8a-5372-9b90-0c9aee199e5d,5,rfc,,,deterministic hash of a namespace and a name; nothing can be decoded
6,00000000-0000-0000-0000-
…

Privacy

UUID Version Detector runs entirely in your browser. The text or files you provide are processed on your device and are not uploaded, logged or stored on our servers.

Limitations

Only v1, v6 and v7 carry a usable timestamp, and it is whatever the generator’s clock said; it is not proof of when a record was created. Name-based and random UUIDs cannot be decoded further.

Frequently asked questions

How is this different from the UUID validator?

The validator answers whether each value is a well-formed UUID. This tool assumes you already have UUIDs and focuses on decoding them: version names, variants, timestamps, nodes and a per-version count.

Why does a UUID show “non-RFC variant”?

The variant bits in the fourth group are not 10xx, so the version digit has no defined meaning. Older Microsoft GUIDs and some hand-made 128-bit IDs look like this.

Can it tell v4 from v7 for a value without a timestamp?

Yes, the version digit is explicit: 4 means random, 7 means Unix-time ordered. For v7 the first 12 hex digits are the millisecond timestamp, which the tool converts to a UTC date.

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