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 01a1af4a-a628-7366-bc41-06dfee7f9573

Version 7 Unix Epoch time-based Sortable by time
01a1af4aa628 unix_ts_ms
7 ver
366 rand_a
bc4106dfee7f9573 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-06T05:17:47.432Z
Unix: 1793942267432 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) 01a1af4a-a628-7366-bc41-06dfee7f9573
Uppercase 01A1AF4A-A628-7366-BC41-06DFEE7F9573
Microsoft GUID (braces) {01A1AF4A-A628-7366-BC41-06DFEE7F9573}
URN urn:uuid:01a1af4a-a628-7366-bc41-06dfee7f9573
32 hex digits 01a1af4aa6287366bc4106dfee7f9573
Base64 (RFC byte order) AaGvSqYoc2a8QQbf7n+Vcw==
128-bit integer (decimal) 2168743125997101849388812874853356915
.NET Guid.ToByteArray() (hex) 4aafa10128a66673bc4106dfee7f9573
.NET Guid bytes (Base64) Sq+hASimZnO8QQbf7n+Vcw==

API: /api/decode/01a1af4a-a628-7366-bc41-06dfee7f9573

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.