UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1ddcf-253c-70eb-9d6a-74d9f69a0f27

Version 7 Unix Epoch time-based Sortable by time

01a1ddcf253c unix_ts_ms

7 ver

0eb rand_a

9d6a74d9f69a0f27 var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-15T06:05:02.652Z` Unix: 1794722702652 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-15T06:05:02.652Z
Unix: 1794722702652 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)	`01a1ddcf-253c-70eb-9d6a-74d9f69a0f27`
Uppercase	`01A1DDCF-253C-70EB-9D6A-74D9F69A0F27`
Microsoft GUID (braces)	`{01A1DDCF-253C-70EB-9D6A-74D9F69A0F27}`
URN	`urn:uuid:01a1ddcf-253c-70eb-9d6a-74d9f69a0f27`
32 hex digits	`01a1ddcf253c70eb9d6a74d9f69a0f27`
Base64 (RFC byte order)	`AaHdzyU8cOudanTZ9poPJw==`
128-bit integer (decimal)	`2169686614285084756919382281704574759`
.NET Guid.ToByteArray() (hex)	`cfdda1013c25eb709d6a74d9f69a0f27`
.NET Guid bytes (Base64)	`z92hATwl63CdanTZ9poPJw==`

Standard (lowercase)

01a1ddcf-253c-70eb-9d6a-74d9f69a0f27

Uppercase

01A1DDCF-253C-70EB-9D6A-74D9F69A0F27

Microsoft GUID (braces)

{01A1DDCF-253C-70EB-9D6A-74D9F69A0F27}

URN

urn:uuid:01a1ddcf-253c-70eb-9d6a-74d9f69a0f27

32 hex digits

01a1ddcf253c70eb9d6a74d9f69a0f27

Base64 (RFC byte order)

AaHdzyU8cOudanTZ9poPJw==

128-bit integer (decimal)

2169686614285084756919382281704574759

.NET Guid.ToByteArray() (hex)

cfdda1013c25eb709d6a74d9f69a0f27

.NET Guid bytes (Base64)

z92hATwl63CdanTZ9poPJw==

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 01a1ddcf-253c-70eb-9d6a-74d9f69a0f27 Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1ddcf-253c-70eb-9d6a-74d9f69a0f27`