UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1da42-0347-72b5-986a-d30bed84a9ae

Version 7 Unix Epoch time-based Sortable by time

01a1da420347 unix_ts_ms

7 ver

2b5 rand_a

986ad30bed84a9ae var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-14T13:32:01.735Z` Unix: 1794663121735 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-14T13:32:01.735Z
Unix: 1794663121735 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)	`01a1da42-0347-72b5-986a-d30bed84a9ae`
Uppercase	`01A1DA42-0347-72B5-986A-D30BED84A9AE`
Microsoft GUID (braces)	`{01A1DA42-0347-72B5-986A-D30BED84A9AE}`
URN	`urn:uuid:01a1da42-0347-72b5-986a-d30bed84a9ae`
32 hex digits	`01a1da42034772b5986ad30bed84a9ae`
Base64 (RFC byte order)	`AaHaQgNHcrWYatML7YSprg==`
128-bit integer (decimal)	`2169614585376175588975139692006910382`
.NET Guid.ToByteArray() (hex)	`42daa1014703b572986ad30bed84a9ae`
.NET Guid bytes (Base64)	`QtqhAUcDtXKYatML7YSprg==`

Standard (lowercase)

01a1da42-0347-72b5-986a-d30bed84a9ae

Uppercase

01A1DA42-0347-72B5-986A-D30BED84A9AE

Microsoft GUID (braces)

{01A1DA42-0347-72B5-986A-D30BED84A9AE}

URN

urn:uuid:01a1da42-0347-72b5-986a-d30bed84a9ae

32 hex digits

01a1da42034772b5986ad30bed84a9ae

Base64 (RFC byte order)

AaHaQgNHcrWYatML7YSprg==

128-bit integer (decimal)

2169614585376175588975139692006910382

.NET Guid.ToByteArray() (hex)

42daa1014703b572986ad30bed84a9ae

.NET Guid bytes (Base64)

QtqhAUcDtXKYatML7YSprg==

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 01a1da42-0347-72b5-986a-d30bed84a9ae Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1da42-0347-72b5-986a-d30bed84a9ae`