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 01a19ce9-8fdc-725f-a470-de3cdc65f10e

Version 7 Unix Epoch time-based Sortable by time
01a19ce98fdc unix_ts_ms
7 ver
25f rand_a
a470de3cdc65f10e var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-02T15:38:34.844Z
Unix: 1793633914844 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) 01a19ce9-8fdc-725f-a470-de3cdc65f10e
Uppercase 01A19CE9-8FDC-725F-A470-DE3CDC65F10E
Microsoft GUID (braces) {01A19CE9-8FDC-725F-A470-DE3CDC65F10E}
URN urn:uuid:01a19ce9-8fdc-725f-a470-de3cdc65f10e
32 hex digits 01a19ce98fdc725fa470de3cdc65f10e
Base64 (RFC byte order) AaGc6Y/ccl+kcN483GXxDg==
128-bit integer (decimal) 2168370350591918804110524396855488782
.NET Guid.ToByteArray() (hex) e99ca101dc8f5f72a470de3cdc65f10e
.NET Guid bytes (Base64) 6ZyhAdyPX3KkcN483GXxDg==

API: /api/decode/01a19ce9-8fdc-725f-a470-de3cdc65f10e

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.