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 01a1c31e-56e3-73d0-b445-4a9f1846d8ca

Version 7 Unix Epoch time-based Sortable by time
01a1c31e56e3 unix_ts_ms
7 ver
3d0 rand_a
b4454a9f1846d8ca var + rand_b
Version7 Unix Epoch time-based
VariantRFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)
Timestamp (UTC)2026-11-10T01:41:47.875Z
Unix: 1794274907875 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) 01a1c31e-56e3-73d0-b445-4a9f1846d8ca
Uppercase 01A1C31E-56E3-73D0-B445-4A9F1846D8CA
Microsoft GUID (braces) {01A1C31E-56E3-73D0-B445-4A9F1846D8CA}
URN urn:uuid:01a1c31e-56e3-73d0-b445-4a9f1846d8ca
32 hex digits 01a1c31e56e373d0b4454a9f1846d8ca
Base64 (RFC byte order) AaHDHlbjc9C0RUqfGEbYyg==
128-bit integer (decimal) 2169145263617294552506379310767462602
.NET Guid.ToByteArray() (hex) 1ec3a101e356d073b4454a9f1846d8ca
.NET Guid bytes (Base64) HsOhAeNW0HO0RUqfGEbYyg==

API: /api/decode/01a1c31e-56e3-73d0-b445-4a9f1846d8ca

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.