UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1ccb8-a95a-72d5-8bdd-e7ff0d773b26

Version 7 Unix Epoch time-based Sortable by time

01a1ccb8a95a unix_ts_ms

7 ver

2d5 rand_a

8bdde7ff0d773b26 var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-11T22:26:56.474Z` Unix: 1794436016474 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits 10)

Timestamp (UTC)

2026-11-11T22:26:56.474Z
Unix: 1794436016474 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)	`01a1ccb8-a95a-72d5-8bdd-e7ff0d773b26`
Uppercase	`01A1CCB8-A95A-72D5-8BDD-E7FF0D773B26`
Microsoft GUID (braces)	`{01A1CCB8-A95A-72D5-8BDD-E7FF0D773B26}`
URN	`urn:uuid:01a1ccb8-a95a-72d5-8bdd-e7ff0d773b26`
32 hex digits	`01a1ccb8a95a72d58bdde7ff0d773b26`
Base64 (RFC byte order)	`AaHMuKlactWL3ef/DXc7Jg==`
128-bit integer (decimal)	`2169340031962382959088454124288031526`
.NET Guid.ToByteArray() (hex)	`b8cca1015aa9d5728bdde7ff0d773b26`
.NET Guid bytes (Base64)	`uMyhAVqp1XKL3ef/DXc7Jg==`

Standard (lowercase)

01a1ccb8-a95a-72d5-8bdd-e7ff0d773b26

Uppercase

01A1CCB8-A95A-72D5-8BDD-E7FF0D773B26

Microsoft GUID (braces)

{01A1CCB8-A95A-72D5-8BDD-E7FF0D773B26}

URN

urn:uuid:01a1ccb8-a95a-72d5-8bdd-e7ff0d773b26

32 hex digits

01a1ccb8a95a72d58bdde7ff0d773b26

Base64 (RFC byte order)

AaHMuKlactWL3ef/DXc7Jg==

128-bit integer (decimal)

2169340031962382959088454124288031526

.NET Guid.ToByteArray() (hex)

b8cca1015aa9d5728bdde7ff0d773b26

.NET Guid bytes (Base64)

uMyhAVqp1XKL3ef/DXc7Jg==

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 digit	Meaning	Contains a timestamp?
1	Gregorian time-based	Yes (100 ns since 1582)
2	DCE Security	Partial
3	Name-based, MD5	No
4	Random	No
5	Name-based, SHA-1	No
6	Reordered Gregorian time	Yes (100 ns since 1582)
7	Unix Epoch time	Yes (ms since 1970)
8	Custom	Only if your format has one

Variant digit

Binary	Hex digit	Variant
`0xxx`	0 - 7	Reserved, NCS backward compatibility
`10xx`	8 - b	RFC 9562 (the standard variant)
`110x`	c - d	Reserved, Microsoft backward compatibility
`111x`	e - f	Reserved 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.

UUID Validator & Decoder

Valid 01a1ccb8-a95a-72d5-8bdd-e7ff0d773b26 Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1ccb8-a95a-72d5-8bdd-e7ff0d773b26`