UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1ac05-30cc-7068-9258-ad595d9118dc

Version 7 Unix Epoch time-based Sortable by time

01a1ac0530cc unix_ts_ms

7 ver

068 rand_a

9258ad595d9118dc var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-05T14:03:03.756Z` Unix: 1793887383756 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-05T14:03:03.756Z
Unix: 1793887383756 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)	`01a1ac05-30cc-7068-9258-ad595d9118dc`
Uppercase	`01A1AC05-30CC-7068-9258-AD595D9118DC`
Microsoft GUID (braces)	`{01A1AC05-30CC-7068-9258-AD595D9118DC}`
URN	`urn:uuid:01a1ac05-30cc-7068-9258-ad595d9118dc`
32 hex digits	`01a1ac0530cc70689258ad595d9118dc`
Base64 (RFC byte order)	`AaGsBTDMcGiSWK1ZXZEY3A==`
128-bit integer (decimal)	`2168676775704095952410605707534080220`
.NET Guid.ToByteArray() (hex)	`05aca101cc3068709258ad595d9118dc`
.NET Guid bytes (Base64)	`BayhAcwwaHCSWK1ZXZEY3A==`

Standard (lowercase)

01a1ac05-30cc-7068-9258-ad595d9118dc

Uppercase

01A1AC05-30CC-7068-9258-AD595D9118DC

Microsoft GUID (braces)

{01A1AC05-30CC-7068-9258-AD595D9118DC}

URN

urn:uuid:01a1ac05-30cc-7068-9258-ad595d9118dc

32 hex digits

01a1ac0530cc70689258ad595d9118dc

Base64 (RFC byte order)

AaGsBTDMcGiSWK1ZXZEY3A==

128-bit integer (decimal)

2168676775704095952410605707534080220

.NET Guid.ToByteArray() (hex)

05aca101cc3068709258ad595d9118dc

.NET Guid bytes (Base64)

BayhAcwwaHCSWK1ZXZEY3A==

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 01a1ac05-30cc-7068-9258-ad595d9118dc Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1ac05-30cc-7068-9258-ad595d9118dc`