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 01a1af29-5ef6-7267-8e29-195402a11ee6

Version 7 Unix Epoch time-based Sortable by time
01a1af295ef6 unix_ts_ms
7 ver
267 rand_a
8e29195402a11ee6 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-06T04:41:26.518Z
Unix: 1793940086518 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) 01a1af29-5ef6-7267-8e29-195402a11ee6
Uppercase 01A1AF29-5EF6-7267-8E29-195402A11EE6
Microsoft GUID (braces) {01A1AF29-5EF6-7267-8E29-195402A11EE6}
URN urn:uuid:01a1af29-5ef6-7267-8e29-195402a11ee6
32 hex digits 01a1af295ef672678e29195402a11ee6
Base64 (RFC byte order) AaGvKV72cmeOKRlUAqEe5g==
128-bit integer (decimal) 2168740489433852183128317718350077670
.NET Guid.ToByteArray() (hex) 29afa101f65e67728e29195402a11ee6
.NET Guid bytes (Base64) Ka+hAfZeZ3KOKRlUAqEe5g==

API: /api/decode/01a1af29-5ef6-7267-8e29-195402a11ee6

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.