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 01a1cde5-c23a-725d-9e36-9b70436cc073

Version 7 Unix Epoch time-based Sortable by time
01a1cde5c23a unix_ts_ms
7 ver
25d rand_a
9e369b70436cc073 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-12T03:55:49.178Z
Unix: 1794455749178 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) 01a1cde5-c23a-725d-9e36-9b70436cc073
Uppercase 01A1CDE5-C23A-725D-9E36-9B70436CC073
Microsoft GUID (braces) {01A1CDE5-C23A-725D-9E36-9B70436CC073}
URN urn:uuid:01a1cde5-c23a-725d-9e36-9b70436cc073
32 hex digits 01a1cde5c23a725d9e369b70436cc073
Base64 (RFC byte order) AaHN5cI6cl2eNptwQ2zAcw==
128-bit integer (decimal) 2169363887337737159672743309851017331
.NET Guid.ToByteArray() (hex) e5cda1013ac25d729e369b70436cc073
.NET Guid bytes (Base64) 5c2hATrCXXKeNptwQ2zAcw==

API: /api/decode/01a1cde5-c23a-725d-9e36-9b70436cc073

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.