UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1919c-e3f0-7073-818d-a645b833f5a9

Version 7 Unix Epoch time-based Sortable by time

01a1919ce3f0 unix_ts_ms

7 ver

073 rand_a

818da645b833f5a9 var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-10-31T10:59:00.720Z` Unix: 1793444340720 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-10-31T10:59:00.720Z
Unix: 1793444340720 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)	`01a1919c-e3f0-7073-818d-a645b833f5a9`
Uppercase	`01A1919C-E3F0-7073-818D-A645B833F5A9`
Microsoft GUID (braces)	`{01A1919C-E3F0-7073-818D-A645B833F5A9}`
URN	`urn:uuid:01a1919c-e3f0-7073-818d-a645b833f5a9`
32 hex digits	`01a1919ce3f07073818da645b833f5a9`
Base64 (RFC byte order)	`AaGRnOPwcHOBjaZFuDP1qQ==`
128-bit integer (decimal)	`2168141169538675300455145813876929961`
.NET Guid.ToByteArray() (hex)	`9c91a101f0e37370818da645b833f5a9`
.NET Guid bytes (Base64)	`nJGhAfDjc3CBjaZFuDP1qQ==`

Standard (lowercase)

01a1919c-e3f0-7073-818d-a645b833f5a9

Uppercase

01A1919C-E3F0-7073-818D-A645B833F5A9

Microsoft GUID (braces)

{01A1919C-E3F0-7073-818D-A645B833F5A9}

URN

urn:uuid:01a1919c-e3f0-7073-818d-a645b833f5a9

32 hex digits

01a1919ce3f07073818da645b833f5a9

Base64 (RFC byte order)

AaGRnOPwcHOBjaZFuDP1qQ==

128-bit integer (decimal)

2168141169538675300455145813876929961

.NET Guid.ToByteArray() (hex)

9c91a101f0e37370818da645b833f5a9

.NET Guid bytes (Base64)

nJGhAfDjc3CBjaZFuDP1qQ==

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 01a1919c-e3f0-7073-818d-a645b833f5a9 Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1919c-e3f0-7073-818d-a645b833f5a9`