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 01a1c68c-4b61-7173-8583-e389d5d3b5c4

Version 7 Unix Epoch time-based Sortable by time
01a1c68c4b61 unix_ts_ms
7 ver
173 rand_a
8583e389d5d3b5c4 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-10T17:40:45.537Z
Unix: 1794332445537 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) 01a1c68c-4b61-7173-8583-e389d5d3b5c4
Uppercase 01A1C68C-4B61-7173-8583-E389D5D3B5C4
Microsoft GUID (braces) {01A1C68C-4B61-7173-8583-E389D5D3B5C4}
URN urn:uuid:01a1c68c-4b61-7173-8583-e389d5d3b5c4
32 hex digits 01a1c68c4b6171738583e389d5d3b5c4
Base64 (RFC byte order) AaHGjEthcXOFg+OJ1dO1xA==
128-bit integer (decimal) 2169214822382475448360836962136077764
.NET Guid.ToByteArray() (hex) 8cc6a101614b73718583e389d5d3b5c4
.NET Guid bytes (Base64) jMahAWFLc3GFg+OJ1dO1xA==

API: /api/decode/01a1c68c-4b61-7173-8583-e389d5d3b5c4

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.