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 01a1e0a5-91b2-71ac-a478-d9e7c639a82c

Version 7 Unix Epoch time-based Sortable by time
01a1e0a591b2 unix_ts_ms
7 ver
1ac rand_a
a478d9e7c639a82c var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-15T19:18:29.554Z
Unix: 1794770309554 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) 01a1e0a5-91b2-71ac-a478-d9e7c639a82c
Uppercase 01A1E0A5-91B2-71AC-A478-D9E7C639A82C
Microsoft GUID (braces) {01A1E0A5-91B2-71AC-A478-D9E7C639A82C}
URN urn:uuid:01a1e0a5-91b2-71ac-a478-d9e7c639a82c
32 hex digits 01a1e0a591b271aca478d9e7c639a82c
Base64 (RFC byte order) AaHgpZGycaykeNnnxjmoLA==
128-bit integer (decimal) 2169744167498107980978330003379431468
.NET Guid.ToByteArray() (hex) a5e0a101b291ac71a478d9e7c639a82c
.NET Guid bytes (Base64) peChAbKRrHGkeNnnxjmoLA==

API: /api/decode/01a1e0a5-91b2-71ac-a478-d9e7c639a82c

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.