UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a19fdc-f0f3-7350-9f73-089dee7fa508

Version 7 Unix Epoch time-based Sortable by time

01a19fdcf0f3 unix_ts_ms

7 ver

350 rand_a

9f73089dee7fa508 var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-03T05:23:39.379Z` Unix: 1793683419379 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-03T05:23:39.379Z
Unix: 1793683419379 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)	`01a19fdc-f0f3-7350-9f73-089dee7fa508`
Uppercase	`01A19FDC-F0F3-7350-9F73-089DEE7FA508`
Microsoft GUID (braces)	`{01A19FDC-F0F3-7350-9F73-089DEE7FA508}`
URN	`urn:uuid:01a19fdc-f0f3-7350-9f73-089dee7fa508`
32 hex digits	`01a19fdcf0f373509f73089dee7fa508`
Base64 (RFC byte order)	`AaGf3PDzc1Cfcwid7n+lCA==`
128-bit integer (decimal)	`2168430197902472765512659000029586696`
.NET Guid.ToByteArray() (hex)	`dc9fa101f3f050739f73089dee7fa508`
.NET Guid bytes (Base64)	`3J+hAfPwUHOfcwid7n+lCA==`

Standard (lowercase)

01a19fdc-f0f3-7350-9f73-089dee7fa508

Uppercase

01A19FDC-F0F3-7350-9F73-089DEE7FA508

Microsoft GUID (braces)

{01A19FDC-F0F3-7350-9F73-089DEE7FA508}

URN

urn:uuid:01a19fdc-f0f3-7350-9f73-089dee7fa508

32 hex digits

01a19fdcf0f373509f73089dee7fa508

Base64 (RFC byte order)

AaGf3PDzc1Cfcwid7n+lCA==

128-bit integer (decimal)

2168430197902472765512659000029586696

.NET Guid.ToByteArray() (hex)

dc9fa101f3f050739f73089dee7fa508

.NET Guid bytes (Base64)

3J+hAfPwUHOfcwid7n+lCA==

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 01a19fdc-f0f3-7350-9f73-089dee7fa508 Copy

Formats

How to decode a UUID

Variant digit

Valid `01a19fdc-f0f3-7350-9f73-089dee7fa508`