UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1a9f3-4cc7-719e-9a88-c25aa54c0db8

Version 7 Unix Epoch time-based Sortable by time

01a1a9f34cc7 unix_ts_ms

7 ver

19e rand_a

9a88c25aa54c0db8 var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-05T04:24:16.839Z` Unix: 1793852656839 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-05T04:24:16.839Z
Unix: 1793852656839 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)	`01a1a9f3-4cc7-719e-9a88-c25aa54c0db8`
Uppercase	`01A1A9F3-4CC7-719E-9A88-C25AA54C0DB8`
Microsoft GUID (braces)	`{01A1A9F3-4CC7-719E-9A88-C25AA54C0DB8}`
URN	`urn:uuid:01a1a9f3-4cc7-719e-9a88-c25aa54c0db8`
32 hex digits	`01a1a9f34cc7719e9a88c25aa54c0db8`
Base64 (RFC byte order)	`AaGp80zHcZ6aiMJapUwNuA==`
128-bit integer (decimal)	`2168634793437504757291927404049862072`
.NET Guid.ToByteArray() (hex)	`f3a9a101c74c9e719a88c25aa54c0db8`
.NET Guid bytes (Base64)	`86mhAcdMnnGaiMJapUwNuA==`

Standard (lowercase)

01a1a9f3-4cc7-719e-9a88-c25aa54c0db8

Uppercase

01A1A9F3-4CC7-719E-9A88-C25AA54C0DB8

Microsoft GUID (braces)

{01A1A9F3-4CC7-719E-9A88-C25AA54C0DB8}

URN

urn:uuid:01a1a9f3-4cc7-719e-9a88-c25aa54c0db8

32 hex digits

01a1a9f34cc7719e9a88c25aa54c0db8

Base64 (RFC byte order)

AaGp80zHcZ6aiMJapUwNuA==

128-bit integer (decimal)

2168634793437504757291927404049862072

.NET Guid.ToByteArray() (hex)

f3a9a101c74c9e719a88c25aa54c0db8

.NET Guid bytes (Base64)

86mhAcdMnnGaiMJapUwNuA==

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 01a1a9f3-4cc7-719e-9a88-c25aa54c0db8 Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1a9f3-4cc7-719e-9a88-c25aa54c0db8`