UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1d319-8b09-707f-b4c4-d67d53f6e800

Version 7 Unix Epoch time-based Sortable by time

01a1d3198b09 unix_ts_ms

7 ver

07f rand_a

b4c4d67d53f6e800 var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-13T04:10:29.001Z` Unix: 1794543029001 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-13T04:10:29.001Z
Unix: 1794543029001 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)	`01a1d319-8b09-707f-b4c4-d67d53f6e800`
Uppercase	`01A1D319-8B09-707F-B4C4-D67D53F6E800`
Microsoft GUID (braces)	`{01A1D319-8B09-707F-B4C4-D67D53F6E800}`
URN	`urn:uuid:01a1d319-8b09-707f-b4c4-d67d53f6e800`
32 hex digits	`01a1d3198b09707fb4c4d67d53f6e800`
Base64 (RFC byte order)	`AaHTGYsJcH+0xNZ9U/boAA==`
128-bit integer (decimal)	`2169469402169284438516956510629062656`
.NET Guid.ToByteArray() (hex)	`19d3a101098b7f70b4c4d67d53f6e800`
.NET Guid bytes (Base64)	`GdOhAQmLf3C0xNZ9U/boAA==`

Standard (lowercase)

01a1d319-8b09-707f-b4c4-d67d53f6e800

Uppercase

01A1D319-8B09-707F-B4C4-D67D53F6E800

Microsoft GUID (braces)

{01A1D319-8B09-707F-B4C4-D67D53F6E800}

URN

urn:uuid:01a1d319-8b09-707f-b4c4-d67d53f6e800

32 hex digits

01a1d3198b09707fb4c4d67d53f6e800

Base64 (RFC byte order)

AaHTGYsJcH+0xNZ9U/boAA==

128-bit integer (decimal)

2169469402169284438516956510629062656

.NET Guid.ToByteArray() (hex)

19d3a101098b7f70b4c4d67d53f6e800

.NET Guid bytes (Base64)

GdOhAQmLf3C0xNZ9U/boAA==

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 01a1d319-8b09-707f-b4c4-d67d53f6e800 Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1d319-8b09-707f-b4c4-d67d53f6e800`