UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a16fcc-3e91-7142-9b11-eb1d303c60ff

Version 7 Unix Epoch time-based Sortable by time

01a16fcc3e91 unix_ts_ms

7 ver

142 rand_a

9b11eb1d303c60ff var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-10-24T21:23:38.769Z` Unix: 1792877018769 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-10-24T21:23:38.769Z
Unix: 1792877018769 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)	`01a16fcc-3e91-7142-9b11-eb1d303c60ff`
Uppercase	`01A16FCC-3E91-7142-9B11-EB1D303C60FF`
Microsoft GUID (braces)	`{01A16FCC-3E91-7142-9B11-EB1D303C60FF}`
URN	`urn:uuid:01a16fcc-3e91-7142-9b11-eb1d303c60ff`
32 hex digits	`01a16fcc3e9171429b11eb1d303c60ff`
Base64 (RFC byte order)	`AaFvzD6RcUKbEesdMDxg/w==`
128-bit integer (decimal)	`2167455319384081075278303484230525183`
.NET Guid.ToByteArray() (hex)	`cc6fa101913e42719b11eb1d303c60ff`
.NET Guid bytes (Base64)	`zG+hAZE+QnGbEesdMDxg/w==`

Standard (lowercase)

01a16fcc-3e91-7142-9b11-eb1d303c60ff

Uppercase

01A16FCC-3E91-7142-9B11-EB1D303C60FF

Microsoft GUID (braces)

{01A16FCC-3E91-7142-9B11-EB1D303C60FF}

URN

urn:uuid:01a16fcc-3e91-7142-9b11-eb1d303c60ff

32 hex digits

01a16fcc3e9171429b11eb1d303c60ff

Base64 (RFC byte order)

AaFvzD6RcUKbEesdMDxg/w==

128-bit integer (decimal)

2167455319384081075278303484230525183

.NET Guid.ToByteArray() (hex)

cc6fa101913e42719b11eb1d303c60ff

.NET Guid bytes (Base64)

zG+hAZE+QnGbEesdMDxg/w==

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 01a16fcc-3e91-7142-9b11-eb1d303c60ff Copy

Formats

How to decode a UUID

Variant digit

Valid `01a16fcc-3e91-7142-9b11-eb1d303c60ff`