UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1dff2-601a-7394-8327-827a968ab700

Version 7 Unix Epoch time-based Sortable by time

01a1dff2601a unix_ts_ms

7 ver

394 rand_a

8327827a968ab700 var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-15T16:02:45.914Z` Unix: 1794758565914 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-15T16:02:45.914Z
Unix: 1794758565914 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)	`01a1dff2-601a-7394-8327-827a968ab700`
Uppercase	`01A1DFF2-601A-7394-8327-827A968AB700`
Microsoft GUID (braces)	`{01A1DFF2-601A-7394-8327-827A968AB700}`
URN	`urn:uuid:01a1dff2-601a-7394-8327-827a968ab700`
32 hex digits	`01a1dff2601a73948327827a968ab700`
Base64 (RFC byte order)	`AaHf8mAac5SDJ4J6loq3AA==`
128-bit integer (decimal)	`2169729970308504721444880524375668480`
.NET Guid.ToByteArray() (hex)	`f2dfa1011a6094738327827a968ab700`
.NET Guid bytes (Base64)	`8t+hARpglHODJ4J6loq3AA==`

Standard (lowercase)

01a1dff2-601a-7394-8327-827a968ab700

Uppercase

01A1DFF2-601A-7394-8327-827A968AB700

Microsoft GUID (braces)

{01A1DFF2-601A-7394-8327-827A968AB700}

URN

urn:uuid:01a1dff2-601a-7394-8327-827a968ab700

32 hex digits

01a1dff2601a73948327827a968ab700

Base64 (RFC byte order)

AaHf8mAac5SDJ4J6loq3AA==

128-bit integer (decimal)

2169729970308504721444880524375668480

.NET Guid.ToByteArray() (hex)

f2dfa1011a6094738327827a968ab700

.NET Guid bytes (Base64)

8t+hARpglHODJ4J6loq3AA==

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 01a1dff2-601a-7394-8327-827a968ab700 Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1dff2-601a-7394-8327-827a968ab700`