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 01a170a5-1fdf-7183-9e74-9b17f226d2bb

Version 7 Unix Epoch time-based Sortable by time
01a170a51fdf unix_ts_ms
7 ver
183 rand_a
9e749b17f226d2bb var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-10-25T01:20:32.223Z
Unix: 1792891232223 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) 01a170a5-1fdf-7183-9e74-9b17f226d2bb
Uppercase 01A170A5-1FDF-7183-9E74-9B17F226D2BB
Microsoft GUID (braces) {01A170A5-1FDF-7183-9E74-9B17F226D2BB}
URN urn:uuid:01a170a5-1fdf-7183-9e74-9b17f226d2bb
32 hex digits 01a170a51fdf71839e749b17f226d2bb
Base64 (RFC byte order) AaFwpR/fcYOedJsX8ibSuw==
128-bit integer (decimal) 2167472502395608779390120840908952251
.NET Guid.ToByteArray() (hex) a570a101df1f83719e749b17f226d2bb
.NET Guid bytes (Base64) pXChAd8fg3GedJsX8ibSuw==

API: /api/decode/01a170a5-1fdf-7183-9e74-9b17f226d2bb

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.