UUIDTools.com

UUID Validator & Decoder

Paste a UUID or GUID to check it and see what is inside: version, variant, timestamp and more.

Accepts hyphenated, 32 hex digits, {braces}, urn:uuid:, any case. Try a fresh v7.

Valid d5f77330-dd8b-21f1-af00-318a50afe727

Version 2 DCE Security
d5f77330 local_id
dd8b time_mid
2 ver
1f1 time_high
af var + clock_seq
00 local_domain
318a50afe727 node
Version2 DCE Security
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-11T04:47:29.5388672Z
Unix: 1794372449 s. Approximate: the low 32 bits of the timestamp are replaced by the local identifier, so the true time is up to ~7 minutes later.
Clock sequence47
Node31:8a:50:af:e7:27 Random node ID (multicast bit set; not a real MAC address)
Local domainPerson (POSIX UID) (0)
Local identifier3589763888

Version 2 (DCE Security) is reserved by RFC 9562 but its layout is defined by the DCE 1.1 spec. It is rarely used.

Formats

Standard (lowercase) d5f77330-dd8b-21f1-af00-318a50afe727
Uppercase D5F77330-DD8B-21F1-AF00-318A50AFE727
Microsoft GUID (braces) {D5F77330-DD8B-21F1-AF00-318A50AFE727}
URN urn:uuid:d5f77330-dd8b-21f1-af00-318a50afe727
32 hex digits d5f77330dd8b21f1af00318a50afe727
Base64 (RFC byte order) 1fdzMN2LIfGvADGKUK/nJw==
128-bit integer (decimal) 284410396774865792135357978389559371559
.NET Guid.ToByteArray() (hex) 3073f7d58bddf121af00318a50afe727
.NET Guid bytes (Base64) MHP31Yvd8SGvADGKUK/nJw==

API: /api/decode/d5f77330-dd8b-21f1-af00-318a50afe727

How to decode a UUID

Every RFC 9562 UUID stores its version in the 13th hex digit and its variant in the top bits of the 17th digit:

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
             M = version (1-8)   N = variant (8, 9, a, b = RFC 9562)
Version digitMeaningContains a timestamp?
1Gregorian time-basedYes (100 ns since 1582)
2DCE SecurityPartial
3Name-based, MD5No
4RandomNo
5Name-based, SHA-1No
6Reordered Gregorian timeYes (100 ns since 1582)
7Unix Epoch timeYes (ms since 1970)
8CustomOnly if your format has one

Variant digit

BinaryHex digitVariant
0xxx0 - 7Reserved, NCS backward compatibility
10xx8 - bRFC 9562 (the standard variant)
110xc - dReserved, Microsoft backward compatibility
111xe - fReserved for future definition

The decoder never throws on odd input: unknown versions, legacy variants and the special nil (00000000-…) and max (ffffffff-…) UUIDs all produce a readable result.

Learn more in UUID versions explained.