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 01a1998b-e52b-71fa-8e2f-c0b4d0b9d112

Version 7 Unix Epoch time-based Sortable by time
01a1998be52b unix_ts_ms
7 ver
1fa rand_a
8e2fc0b4d0b9d112 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-01T23:57:24.651Z
Unix: 1793577444651 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) 01a1998b-e52b-71fa-8e2f-c0b4d0b9d112
Uppercase 01A1998B-E52B-71FA-8E2F-C0B4D0B9D112
Microsoft GUID (braces) {01A1998B-E52B-71FA-8E2F-C0B4D0B9D112}
URN urn:uuid:01a1998b-e52b-71fa-8e2f-c0b4d0b9d112
32 hex digits 01a1998be52b71fa8e2fc0b4d0b9d112
Base64 (RFC byte order) AaGZi+UrcfqOL8C00LnREg==
128-bit integer (decimal) 2168302082317560618090658451244568850
.NET Guid.ToByteArray() (hex) 8b99a1012be5fa718e2fc0b4d0b9d112
.NET Guid bytes (Base64) i5mhASvl+nGOL8C00LnREg==

API: /api/decode/01a1998b-e52b-71fa-8e2f-c0b4d0b9d112

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.