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 01a1c0dd-a957-72e0-9a77-cce85e3fcf25

Version 7 Unix Epoch time-based Sortable by time
01a1c0dda957 unix_ts_ms
7 ver
2e0 rand_a
9a77cce85e3fcf25 var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-09T15:11:54.711Z
Unix: 1794237114711 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) 01a1c0dd-a957-72e0-9a77-cce85e3fcf25
Uppercase 01A1C0DD-A957-72E0-9A77-CCE85E3FCF25
Microsoft GUID (braces) {01A1C0DD-A957-72E0-9A77-CCE85E3FCF25}
URN urn:uuid:01a1c0dd-a957-72e0-9a77-cce85e3fcf25
32 hex digits 01a1c0dda95772e09a77cce85e3fcf25
Base64 (RFC byte order) AaHA3alXcuCad8zoXj/PJQ==
128-bit integer (decimal) 2169099574485525593331322320381267749
.NET Guid.ToByteArray() (hex) ddc0a10157a9e0729a77cce85e3fcf25
.NET Guid bytes (Base64) 3cChAVep4HKad8zoXj/PJQ==

API: /api/decode/01a1c0dd-a957-72e0-9a77-cce85e3fcf25

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.