UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a17bb8-ae43-7187-a8b0-2040f62c3952

Version 7 Unix Epoch time-based Sortable by time

01a17bb8ae43 unix_ts_ms

7 ver

187 rand_a

a8b02040f62c3952 var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-10-27T04:57:43.235Z` Unix: 1793077063235 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-10-27T04:57:43.235Z
Unix: 1793077063235 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)	`01a17bb8-ae43-7187-a8b0-2040f62c3952`
Uppercase	`01A17BB8-AE43-7187-A8B0-2040F62C3952`
Microsoft GUID (braces)	`{01A17BB8-AE43-7187-A8B0-2040F62C3952}`
URN	`urn:uuid:01a17bb8-ae43-7187-a8b0-2040f62c3952`
32 hex digits	`01a17bb8ae437187a8b02040f62c3952`
Base64 (RFC byte order)	`AaF7uK5DcYeosCBA9iw5Ug==`
128-bit integer (decimal)	`2167697158304100769903966884448713042`
.NET Guid.ToByteArray() (hex)	`b87ba10143ae8771a8b02040f62c3952`
.NET Guid bytes (Base64)	`uHuhAUOuh3GosCBA9iw5Ug==`

Standard (lowercase)

01a17bb8-ae43-7187-a8b0-2040f62c3952

Uppercase

01A17BB8-AE43-7187-A8B0-2040F62C3952

Microsoft GUID (braces)

{01A17BB8-AE43-7187-A8B0-2040F62C3952}

URN

urn:uuid:01a17bb8-ae43-7187-a8b0-2040f62c3952

32 hex digits

01a17bb8ae437187a8b02040f62c3952

Base64 (RFC byte order)

AaF7uK5DcYeosCBA9iw5Ug==

128-bit integer (decimal)

2167697158304100769903966884448713042

.NET Guid.ToByteArray() (hex)

b87ba10143ae8771a8b02040f62c3952

.NET Guid bytes (Base64)

uHuhAUOuh3GosCBA9iw5Ug==

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 01a17bb8-ae43-7187-a8b0-2040f62c3952 Copy

Formats

How to decode a UUID

Variant digit

Valid `01a17bb8-ae43-7187-a8b0-2040f62c3952`