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 01a1ce52-43cd-736b-8b99-f40462efd4e4

Version 7 Unix Epoch time-based Sortable by time
01a1ce5243cd unix_ts_ms
7 ver
36b rand_a
8b99f40462efd4e4 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-12T05:54:20.237Z
Unix: 1794462860237 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) 01a1ce52-43cd-736b-8b99-f40462efd4e4
Uppercase 01A1CE52-43CD-736B-8B99-F40462EFD4E4
Microsoft GUID (braces) {01A1CE52-43CD-736B-8B99-F40462EFD4E4}
URN urn:uuid:01a1ce52-43cd-736b-8b99-f40462efd4e4
32 hex digits 01a1ce5243cd736b8b99f40462efd4e4
Base64 (RFC byte order) AaHOUkPNc2uLmfQEYu/U5A==
128-bit integer (decimal) 2169372484080572041937836797535966436
.NET Guid.ToByteArray() (hex) 52cea101cd436b738b99f40462efd4e4
.NET Guid bytes (Base64) Us6hAc1Da3OLmfQEYu/U5A==

API: /api/decode/01a1ce52-43cd-736b-8b99-f40462efd4e4

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.