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 01a1dc53-0633-72c4-ab3e-6e205c5f5342

Version 7 Unix Epoch time-based Sortable by time
01a1dc530633 unix_ts_ms
7 ver
2c4 rand_a
ab3e6e205c5f5342 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-14T23:09:51.027Z
Unix: 1794697791027 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) 01a1dc53-0633-72c4-ab3e-6e205c5f5342
Uppercase 01A1DC53-0633-72C4-AB3E-6E205C5F5342
Microsoft GUID (braces) {01A1DC53-0633-72C4-AB3E-6E205C5F5342}
URN urn:uuid:01a1dc53-0633-72c4-ab3e-6e205c5f5342
32 hex digits 01a1dc53063372c4ab3e6e205c5f5342
Base64 (RFC byte order) AaHcUwYzcsSrPm4gXF9TQg==
128-bit integer (decimal) 2169656497978422425939228829910258498
.NET Guid.ToByteArray() (hex) 53dca1013306c472ab3e6e205c5f5342
.NET Guid bytes (Base64) U9yhATMGxHKrPm4gXF9TQg==

API: /api/decode/01a1dc53-0633-72c4-ab3e-6e205c5f5342

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.