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 01a18e20-3f73-72e3-9d36-9e383cf9d419

Version 7 Unix Epoch time-based Sortable by time
01a18e203f73 unix_ts_ms
7 ver
2e3 rand_a
9d369e383cf9d419 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-10-30T18:44:00.499Z
Unix: 1793385840499 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) 01a18e20-3f73-72e3-9d36-9e383cf9d419
Uppercase 01A18E20-3F73-72E3-9D36-9E383CF9D419
Microsoft GUID (braces) {01A18E20-3F73-72E3-9D36-9E383CF9D419}
URN urn:uuid:01a18e20-3f73-72e3-9d36-9e383cf9d419
32 hex digits 01a18e203f7372e39d369e383cf9d419
Base64 (RFC byte order) AaGOID9zcuOdNp44PPnUGQ==
128-bit integer (decimal) 2168070447111066751275009905824224281
.NET Guid.ToByteArray() (hex) 208ea101733fe3729d369e383cf9d419
.NET Guid bytes (Base64) II6hAXM/43KdNp44PPnUGQ==

API: /api/decode/01a18e20-3f73-72e3-9d36-9e383cf9d419

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.