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 01a1df8d-9095-739f-b925-4fc122897d5e

Version 7 Unix Epoch time-based Sortable by time
01a1df8d9095 unix_ts_ms
7 ver
39f rand_a
b9254fc122897d5e var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-15T14:12:39.189Z
Unix: 1794751959189 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) 01a1df8d-9095-739f-b925-4fc122897d5e
Uppercase 01A1DF8D-9095-739F-B925-4FC122897D5E
Microsoft GUID (braces) {01A1DF8D-9095-739F-B925-4FC122897D5E}
URN urn:uuid:01a1df8d-9095-739f-b925-4fc122897d5e
32 hex digits 01a1df8d9095739fb9254fc122897d5e
Base64 (RFC byte order) AaHfjZCVc5+5JU/BIol9Xg==
128-bit integer (decimal) 2169721983268069334788622430518213982
.NET Guid.ToByteArray() (hex) 8ddfa10195909f73b9254fc122897d5e
.NET Guid bytes (Base64) jd+hAZWQn3O5JU/BIol9Xg==

API: /api/decode/01a1df8d-9095-739f-b925-4fc122897d5e

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.