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 01a1a657-7f26-72af-9b3d-f82d5b5acb03

Version 7 Unix Epoch time-based Sortable by time
01a1a6577f26 unix_ts_ms
7 ver
2af rand_a
9b3df82d5b5acb03 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-04T11:35:14.470Z
Unix: 1793792114470 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) 01a1a657-7f26-72af-9b3d-f82d5b5acb03
Uppercase 01A1A657-7F26-72AF-9B3D-F82D5B5ACB03
Microsoft GUID (braces) {01A1A657-7F26-72AF-9B3D-F82D5B5ACB03}
URN urn:uuid:01a1a657-7f26-72af-9b3d-f82d5b5acb03
32 hex digits 01a1a6577f2672af9b3df82d5b5acb03
Base64 (RFC byte order) AaGmV38mcq+bPfgtW1rLAw==
128-bit integer (decimal) 2168561602204445056986772449881934595
.NET Guid.ToByteArray() (hex) 57a6a101267faf729b3df82d5b5acb03
.NET Guid bytes (Base64) V6ahASZ/r3KbPfgtW1rLAw==

API: /api/decode/01a1a657-7f26-72af-9b3d-f82d5b5acb03

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.