UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a18103-78bd-7200-8c83-3c5e22a2c717

Version 7 Unix Epoch time-based Sortable by time

01a1810378bd unix_ts_ms

7 ver

200 rand_a

8c833c5e22a2c717 var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-10-28T05:37:30.813Z` Unix: 1793165850813 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-10-28T05:37:30.813Z
Unix: 1793165850813 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)	`01a18103-78bd-7200-8c83-3c5e22a2c717`
Uppercase	`01A18103-78BD-7200-8C83-3C5E22A2C717`
Microsoft GUID (braces)	`{01A18103-78BD-7200-8C83-3C5E22A2C717}`
URN	`urn:uuid:01a18103-78bd-7200-8c83-3c5e22a2c717`
32 hex digits	`01a1810378bd72008c833c5e22a2c717`
Base64 (RFC byte order)	`AaGBA3i9cgCMgzxeIqLHFw==`
128-bit integer (decimal)	`2167804495899608247747542008144774935`
.NET Guid.ToByteArray() (hex)	`0381a101bd7800728c833c5e22a2c717`
.NET Guid bytes (Base64)	`A4GhAb14AHKMgzxeIqLHFw==`

Standard (lowercase)

01a18103-78bd-7200-8c83-3c5e22a2c717

Uppercase

01A18103-78BD-7200-8C83-3C5E22A2C717

Microsoft GUID (braces)

{01A18103-78BD-7200-8C83-3C5E22A2C717}

URN

urn:uuid:01a18103-78bd-7200-8c83-3c5e22a2c717

32 hex digits

01a1810378bd72008c833c5e22a2c717

Base64 (RFC byte order)

AaGBA3i9cgCMgzxeIqLHFw==

128-bit integer (decimal)

2167804495899608247747542008144774935

.NET Guid.ToByteArray() (hex)

0381a101bd7800728c833c5e22a2c717

.NET Guid bytes (Base64)

A4GhAb14AHKMgzxeIqLHFw==

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 01a18103-78bd-7200-8c83-3c5e22a2c717 Copy

Formats

How to decode a UUID

Variant digit

Valid `01a18103-78bd-7200-8c83-3c5e22a2c717`