UUID Validator & Decoder: Version, Variant, Timestamp

Valid 01a1c2f5-b215-70d3-9a9b-79df1f819c20

Version 7 Unix Epoch time-based Sortable by time

01a1c2f5b215 unix_ts_ms

7 ver

0d3 rand_a

9a9b79df1f819c20 var + rand_b

Version	7 Unix Epoch time-based
Variant	RFC 9562 (formerly RFC 4122 / DCE 1.1) (bits `10`)
Timestamp (UTC)	`2026-11-10T00:57:24.245Z` Unix: 1794272244245 ms. Milliseconds.

Version

7 Unix Epoch time-based

Variant

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

Timestamp (UTC)

2026-11-10T00:57:24.245Z
Unix: 1794272244245 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)	`01a1c2f5-b215-70d3-9a9b-79df1f819c20`
Uppercase	`01A1C2F5-B215-70D3-9A9B-79DF1F819C20`
Microsoft GUID (braces)	`{01A1C2F5-B215-70D3-9A9B-79DF1F819C20}`
URN	`urn:uuid:01a1c2f5-b215-70d3-9a9b-79df1f819c20`
32 hex digits	`01a1c2f5b21570d39a9b79df1f819c20`
Base64 (RFC byte order)	`AaHC9bIVcNOam3nfH4GcIA==`
128-bit integer (decimal)	`2169142043486199538783215655405591584`
.NET Guid.ToByteArray() (hex)	`f5c2a10115b2d3709a9b79df1f819c20`
.NET Guid bytes (Base64)	`9cKhARWy03Cam3nfH4GcIA==`

Standard (lowercase)

01a1c2f5-b215-70d3-9a9b-79df1f819c20

Uppercase

01A1C2F5-B215-70D3-9A9B-79DF1F819C20

Microsoft GUID (braces)

{01A1C2F5-B215-70D3-9A9B-79DF1F819C20}

URN

urn:uuid:01a1c2f5-b215-70d3-9a9b-79df1f819c20

32 hex digits

01a1c2f5b21570d39a9b79df1f819c20

Base64 (RFC byte order)

AaHC9bIVcNOam3nfH4GcIA==

128-bit integer (decimal)

2169142043486199538783215655405591584

.NET Guid.ToByteArray() (hex)

f5c2a10115b2d3709a9b79df1f819c20

.NET Guid bytes (Base64)

9cKhARWy03Cam3nfH4GcIA==

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 01a1c2f5-b215-70d3-9a9b-79df1f819c20 Copy

Formats

How to decode a UUID

Variant digit

Valid `01a1c2f5-b215-70d3-9a9b-79df1f819c20`