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 b55b3c27-cdb6-21f1-b000-53fec4d922b3

Version 2 DCE Security
b55b3c27 local_id
cdb6 time_mid
2 ver
1f1 time_high
b0 var + clock_seq
00 local_domain
53fec4d922b3 node
Version2 DCE Security
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-10-22T01:14:59.2937984Z
Unix: 1792631699 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 sequence48
Node53:fe:c4:d9:22:b3 Random node ID (multicast bit set; not a real MAC address)
Local domainPerson (POSIX UID) (0)
Local identifier3042655271

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) b55b3c27-cdb6-21f1-b000-53fec4d922b3
Uppercase B55B3C27-CDB6-21F1-B000-53FEC4D922B3
Microsoft GUID (braces) {B55B3C27-CDB6-21F1-B000-53FEC4D922B3}
URN urn:uuid:b55b3c27-cdb6-21f1-b000-53fec4d922b3
32 hex digits b55b3c27cdb621f1b00053fec4d922b3
Base64 (RFC byte order) tVs8J822IfGwAFP+xNkisw==
128-bit integer (decimal) 241063986349335611275307043025027932851
.NET Guid.ToByteArray() (hex) 273c5bb5b6cdf121b00053fec4d922b3
.NET Guid bytes (Base64) JzxbtbbN8SGwAFP+xNkisw==

API: /api/decode/b55b3c27-cdb6-21f1-b000-53fec4d922b3

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.