UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a19983-9c73-7051-835f-db202760c7ce

Version 7 Unix Epoch time-based Sortable by time

01a199839c73 unix_ts_ms

7 ver

051 rand_a

835fdb202760c7ce var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-01T23:48:21.747Z` Unix: 1793576901747 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-01T23:48:21.747Z
Unix: 1793576901747 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)	`01a19983-9c73-7051-835f-db202760c7ce`
Uppercase	`01A19983-9C73-7051-835F-DB202760C7CE`
Microsoft GUID (braces)	`{01A19983-9C73-7051-835F-DB202760C7CE}`
URN	`urn:uuid:01a19983-9c73-7051-835f-db202760c7ce`
32 hex digits	`01a199839c737051835fdb202760c7ce`
Base64 (RFC byte order)	`AaGZg5xzcFGDX9sgJ2DHzg==`
128-bit integer (decimal)	`2168301425986889605384695972785866702`
.NET Guid.ToByteArray() (hex)	`8399a101739c5170835fdb202760c7ce`
.NET Guid bytes (Base64)	`g5mhAXOcUXCDX9sgJ2DHzg==`

Standard (lowercase)

01a19983-9c73-7051-835f-db202760c7ce

Uppercase

01A19983-9C73-7051-835F-DB202760C7CE

Microsoft GUID (braces)

{01A19983-9C73-7051-835F-DB202760C7CE}

URN

urn:uuid:01a19983-9c73-7051-835f-db202760c7ce

32 hex digits

01a199839c737051835fdb202760c7ce

Base64 (RFC byte order)

AaGZg5xzcFGDX9sgJ2DHzg==

128-bit integer (decimal)

2168301425986889605384695972785866702

.NET Guid.ToByteArray() (hex)

8399a101739c5170835fdb202760c7ce

.NET Guid bytes (Base64)

g5mhAXOcUXCDX9sgJ2DHzg==

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 01a19983-9c73-7051-835f-db202760c7ce Copy

Formats

How to decode a UUID

Variant digit

Valid `01a19983-9c73-7051-835f-db202760c7ce`