UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1c966-b9ed-73c4-90de-e806bae8b51e

Version 7 Unix Epoch time-based Sortable by time

01a1c966b9ed unix_ts_ms

7 ver

3c4 rand_a

90dee806bae8b51e var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-11T06:58:35.117Z` Unix: 1794380315117 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-11T06:58:35.117Z
Unix: 1794380315117 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)	`01a1c966-b9ed-73c4-90de-e806bae8b51e`
Uppercase	`01A1C966-B9ED-73C4-90DE-E806BAE8B51E`
Microsoft GUID (braces)	`{01A1C966-B9ED-73C4-90DE-E806BAE8B51E}`
URN	`urn:uuid:01a1c966-b9ed-73c4-90de-e806bae8b51e`
32 hex digits	`01a1c966b9ed73c490dee806bae8b51e`
Base64 (RFC byte order)	`AaHJZrntc8SQ3ugGuui1Hg==`
128-bit integer (decimal)	`2169272693153722496158774294932403486`
.NET Guid.ToByteArray() (hex)	`66c9a101edb9c47390dee806bae8b51e`
.NET Guid bytes (Base64)	`ZsmhAe25xHOQ3ugGuui1Hg==`

Standard (lowercase)

01a1c966-b9ed-73c4-90de-e806bae8b51e

Uppercase

01A1C966-B9ED-73C4-90DE-E806BAE8B51E

Microsoft GUID (braces)

{01A1C966-B9ED-73C4-90DE-E806BAE8B51E}

URN

urn:uuid:01a1c966-b9ed-73c4-90de-e806bae8b51e

32 hex digits

01a1c966b9ed73c490dee806bae8b51e

Base64 (RFC byte order)

AaHJZrntc8SQ3ugGuui1Hg==

128-bit integer (decimal)

2169272693153722496158774294932403486

.NET Guid.ToByteArray() (hex)

66c9a101edb9c47390dee806bae8b51e

.NET Guid bytes (Base64)

ZsmhAe25xHOQ3ugGuui1Hg==

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 01a1c966-b9ed-73c4-90de-e806bae8b51e Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1c966-b9ed-73c4-90de-e806bae8b51e`