UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1bd3c-7b4d-71cf-b6b8-33fcfaa68c1a

Version 7 Unix Epoch time-based Sortable by time

01a1bd3c7b4d unix_ts_ms

7 ver

1cf rand_a

b6b833fcfaa68c1a var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-08T22:16:59.981Z` Unix: 1794176219981 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-08T22:16:59.981Z
Unix: 1794176219981 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)	`01a1bd3c-7b4d-71cf-b6b8-33fcfaa68c1a`
Uppercase	`01A1BD3C-7B4D-71CF-B6B8-33FCFAA68C1A`
Microsoft GUID (braces)	`{01A1BD3C-7B4D-71CF-B6B8-33FCFAA68C1A}`
URN	`urn:uuid:01a1bd3c-7b4d-71cf-b6b8-33fcfaa68c1a`
32 hex digits	`01a1bd3c7b4d71cfb6b833fcfaa68c1a`
Base64 (RFC byte order)	`AaG9PHtNcc+2uDP8+qaMGg==`
128-bit integer (decimal)	`2169025957274145097858286712049273882`
.NET Guid.ToByteArray() (hex)	`3cbda1014d7bcf71b6b833fcfaa68c1a`
.NET Guid bytes (Base64)	`PL2hAU17z3G2uDP8+qaMGg==`

Standard (lowercase)

01a1bd3c-7b4d-71cf-b6b8-33fcfaa68c1a

Uppercase

01A1BD3C-7B4D-71CF-B6B8-33FCFAA68C1A

Microsoft GUID (braces)

{01A1BD3C-7B4D-71CF-B6B8-33FCFAA68C1A}

URN

urn:uuid:01a1bd3c-7b4d-71cf-b6b8-33fcfaa68c1a

32 hex digits

01a1bd3c7b4d71cfb6b833fcfaa68c1a

Base64 (RFC byte order)

AaG9PHtNcc+2uDP8+qaMGg==

128-bit integer (decimal)

2169025957274145097858286712049273882

.NET Guid.ToByteArray() (hex)

3cbda1014d7bcf71b6b833fcfaa68c1a

.NET Guid bytes (Base64)

PL2hAU17z3G2uDP8+qaMGg==

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 01a1bd3c-7b4d-71cf-b6b8-33fcfaa68c1a Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1bd3c-7b4d-71cf-b6b8-33fcfaa68c1a`