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 01a191a0-1c84-71b1-84c8-540139c4bade

Version 7 Unix Epoch time-based Sortable by time
01a191a01c84 unix_ts_ms
7 ver
1b1 rand_a
84c8540139c4bade var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-10-31T11:02:31.812Z
Unix: 1793444551812 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) 01a191a0-1c84-71b1-84c8-540139c4bade
Uppercase 01A191A0-1C84-71B1-84C8-540139C4BADE
Microsoft GUID (braces) {01A191A0-1C84-71B1-84C8-540139C4BADE}
URN urn:uuid:01a191a0-1c84-71b1-84c8-540139c4bade
32 hex digits 01a191a01c8471b184c8540139c4bade
Base64 (RFC byte order) AaGRoByEcbGEyFQBOcS63g==
128-bit integer (decimal) 2168141424733250280843752352197688030
.NET Guid.ToByteArray() (hex) a091a101841cb17184c8540139c4bade
.NET Guid bytes (Base64) oJGhAYQcsXGEyFQBOcS63g==

API: /api/decode/01a191a0-1c84-71b1-84c8-540139c4bade

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.