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 01a1dc54-a30d-7117-91db-111adb3ad9f1

Version 7 Unix Epoch time-based Sortable by time
01a1dc54a30d unix_ts_ms
7 ver
117 rand_a
91db111adb3ad9f1 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-14T23:11:36.717Z
Unix: 1794697896717 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) 01a1dc54-a30d-7117-91db-111adb3ad9f1
Uppercase 01A1DC54-A30D-7117-91DB-111ADB3AD9F1
Microsoft GUID (braces) {01A1DC54-A30D-7117-91DB-111ADB3AD9F1}
URN urn:uuid:01a1dc54-a30d-7117-91db-111adb3ad9f1
32 hex digits 01a1dc54a30d711791db111adb3ad9f1
Base64 (RFC byte order) AaHcVKMNcReR2xEa2zrZ8Q==
128-bit integer (decimal) 2169656625749784385526770531342932465
.NET Guid.ToByteArray() (hex) 54dca1010da3177191db111adb3ad9f1
.NET Guid bytes (Base64) VNyhAQ2jF3GR2xEa2zrZ8Q==

API: /api/decode/01a1dc54-a30d-7117-91db-111adb3ad9f1

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.