UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a17904-51bb-716f-9026-930d967f3eda

Version 7 Unix Epoch time-based Sortable by time

01a1790451bb unix_ts_ms

7 ver

16f rand_a

9026930d967f3eda var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-10-26T16:21:28.635Z` Unix: 1793031688635 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-10-26T16:21:28.635Z
Unix: 1793031688635 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)	`01a17904-51bb-716f-9026-930d967f3eda`
Uppercase	`01A17904-51BB-716F-9026-930D967F3EDA`
Microsoft GUID (braces)	`{01A17904-51BB-716F-9026-930D967F3EDA}`
URN	`urn:uuid:01a17904-51bb-716f-9026-930d967f3eda`
32 hex digits	`01a1790451bb716f9026930d967f3eda`
Base64 (RFC byte order)	`AaF5BFG7cW+QJpMNln8+2g==`
128-bit integer (decimal)	`2167642303778605639461058912058293978`
.NET Guid.ToByteArray() (hex)	`0479a101bb516f719026930d967f3eda`
.NET Guid bytes (Base64)	`BHmhAbtRb3GQJpMNln8+2g==`

Standard (lowercase)

01a17904-51bb-716f-9026-930d967f3eda

Uppercase

01A17904-51BB-716F-9026-930D967F3EDA

Microsoft GUID (braces)

{01A17904-51BB-716F-9026-930D967F3EDA}

URN

urn:uuid:01a17904-51bb-716f-9026-930d967f3eda

32 hex digits

01a1790451bb716f9026930d967f3eda

Base64 (RFC byte order)

AaF5BFG7cW+QJpMNln8+2g==

128-bit integer (decimal)

2167642303778605639461058912058293978

.NET Guid.ToByteArray() (hex)

0479a101bb516f719026930d967f3eda

.NET Guid bytes (Base64)

BHmhAbtRb3GQJpMNln8+2g==

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 01a17904-51bb-716f-9026-930d967f3eda Copy

Formats

How to decode a UUID

Variant digit

Valid `01a17904-51bb-716f-9026-930d967f3eda`