UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1d49e-a7c8-73a7-95d4-b7e09f8030aa

Version 7 Unix Epoch time-based Sortable by time

01a1d49ea7c8 unix_ts_ms

7 ver

3a7 rand_a

95d4b7e09f8030aa var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-13T11:15:29.864Z` Unix: 1794568529864 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-13T11:15:29.864Z
Unix: 1794568529864 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)	`01a1d49e-a7c8-73a7-95d4-b7e09f8030aa`
Uppercase	`01A1D49E-A7C8-73A7-95D4-B7E09F8030AA`
Microsoft GUID (braces)	`{01A1D49E-A7C8-73A7-95D4-B7E09F8030AA}`
URN	`urn:uuid:01a1d49e-a7c8-73a7-95d4-b7e09f8030aa`
32 hex digits	`01a1d49ea7c873a795d4b7e09f8030aa`
Base64 (RFC byte order)	`AaHUnqfIc6eV1Lfgn4Awqg==`
128-bit integer (decimal)	`2169500230821002496628232579266392234`
.NET Guid.ToByteArray() (hex)	`9ed4a101c8a7a77395d4b7e09f8030aa`
.NET Guid bytes (Base64)	`ntShAcinp3OV1Lfgn4Awqg==`

Standard (lowercase)

01a1d49e-a7c8-73a7-95d4-b7e09f8030aa

Uppercase

01A1D49E-A7C8-73A7-95D4-B7E09F8030AA

Microsoft GUID (braces)

{01A1D49E-A7C8-73A7-95D4-B7E09F8030AA}

URN

urn:uuid:01a1d49e-a7c8-73a7-95d4-b7e09f8030aa

32 hex digits

01a1d49ea7c873a795d4b7e09f8030aa

Base64 (RFC byte order)

AaHUnqfIc6eV1Lfgn4Awqg==

128-bit integer (decimal)

2169500230821002496628232579266392234

.NET Guid.ToByteArray() (hex)

9ed4a101c8a7a77395d4b7e09f8030aa

.NET Guid bytes (Base64)

ntShAcinp3OV1Lfgn4Awqg==

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 01a1d49e-a7c8-73a7-95d4-b7e09f8030aa Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1d49e-a7c8-73a7-95d4-b7e09f8030aa`