UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1d120-7d9e-7151-b09e-b86098d6bd0c

Version 7 Unix Epoch time-based Sortable by time

01a1d1207d9e unix_ts_ms

7 ver

151 rand_a

b09eb86098d6bd0c var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-12T18:58:49.886Z` Unix: 1794509929886 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-12T18:58:49.886Z
Unix: 1794509929886 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)	`01a1d120-7d9e-7151-b09e-b86098d6bd0c`
Uppercase	`01A1D120-7D9E-7151-B09E-B86098D6BD0C`
Microsoft GUID (braces)	`{01A1D120-7D9E-7151-B09E-B86098D6BD0C}`
URN	`urn:uuid:01a1d120-7d9e-7151-b09e-b86098d6bd0c`
32 hex digits	`01a1d1207d9e7151b09eb86098d6bd0c`
Base64 (RFC byte order)	`AaHRIH2ecVGwnrhgmNa9DA==`
128-bit integer (decimal)	`2169429387794558418167516500810185996`
.NET Guid.ToByteArray() (hex)	`20d1a1019e7d5171b09eb86098d6bd0c`
.NET Guid bytes (Base64)	`INGhAZ59UXGwnrhgmNa9DA==`

Standard (lowercase)

01a1d120-7d9e-7151-b09e-b86098d6bd0c

Uppercase

01A1D120-7D9E-7151-B09E-B86098D6BD0C

Microsoft GUID (braces)

{01A1D120-7D9E-7151-B09E-B86098D6BD0C}

URN

urn:uuid:01a1d120-7d9e-7151-b09e-b86098d6bd0c

32 hex digits

01a1d1207d9e7151b09eb86098d6bd0c

Base64 (RFC byte order)

AaHRIH2ecVGwnrhgmNa9DA==

128-bit integer (decimal)

2169429387794558418167516500810185996

.NET Guid.ToByteArray() (hex)

20d1a1019e7d5171b09eb86098d6bd0c

.NET Guid bytes (Base64)

INGhAZ59UXGwnrhgmNa9DA==

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 01a1d120-7d9e-7151-b09e-b86098d6bd0c Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1d120-7d9e-7151-b09e-b86098d6bd0c`