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 01a1c3ca-b48b-737d-be51-f72d051f2384

Version 7 Unix Epoch time-based Sortable by time
01a1c3cab48b unix_ts_ms
7 ver
37d rand_a
be51f72d051f2384 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-10T04:50:04.043Z
Unix: 1794286204043 ms. Milliseconds.

Version 7 UUIDs start with a 48-bit Unix timestamp in milliseconds followed by random bits, so they sort by creation time.

Formats

Standard (lowercase) 01a1c3ca-b48b-737d-be51-f72d051f2384
Uppercase 01A1C3CA-B48B-737D-BE51-F72D051F2384
Microsoft GUID (braces) {01A1C3CA-B48B-737D-BE51-F72D051F2384}
URN urn:uuid:01a1c3ca-b48b-737d-be51-f72d051f2384
32 hex digits 01a1c3cab48b737dbe51f72d051f2384
Base64 (RFC byte order) AaHDyrSLc32+UfctBR8jhA==
128-bit integer (decimal) 2169158919846450926697179740853183364
.NET Guid.ToByteArray() (hex) cac3a1018bb47d73be51f72d051f2384
.NET Guid bytes (Base64) ysOhAYu0fXO+UfctBR8jhA==

API: /api/decode/01a1c3ca-b48b-737d-be51-f72d051f2384

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.