BYTETOOLS

UUID Decoder

Decode any UUID or GUID. Read its version and variant, and pull the creation timestamp out of version 1, 6 and 7 UUIDs instantly.

1
Version
1997-02-03
Created

What this UUID says

Version
Version 1 — time-based (Gregorian timestamp + MAC address)
Variant
RFC 4122 / RFC 9562 (bits 10x)
Created (UTC)
1997-02-03T17:43:12.216Z
Created (local time)
—
Timestamp (100 ns since 1582-10-15)
130742845922168750
Clock sequence
10085
Node (MAC address)
00:A0:C9:1E:6B:F6
Node type
Unicast — likely a real network card MAC

Other representations

Canonical
f81d4fae-7dec-11d0-a765-00a0c91e6bf6
Raw hex (no dashes)
f81d4fae7dec11d0a76500a0c91e6bf6
Base64 (16 bytes)
+B1Prn3sEdCnZQCgyR5r9g==
URN
urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6
Microsoft GUID
{F81D4FAE-7DEC-11D0-A765-00A0C91E6BF6}

What is the UUID Decoder?

The ByteTools UUID Decoder breaks a UUID down into the parts the specification defines. It validates the 8-4-4-4-12 layout, reads the version nibble and the RFC 4122 variant bits, and then decodes whatever else that version carries — for version 1 and 6 that is a 60-bit Gregorian timestamp, a clock sequence and a node identifier, and for version 7 a leading Unix-millisecond timestamp.

  • Supports UUID versions 1 through 8, plus the nil and max UUIDs
  • Timestamps decoded for versions 1, 6 and 7
  • Variant bits identified, including the Microsoft and NCS layouts
  • Flags whether a version 1 node is a real MAC or a random value
  • Canonical, hex, Base64, URN and GUID representations
  • 100% client-side — identifiers never leave your browser

How to use the UUID Decoder

  1. 1

    Paste a UUID into the box — braces, a urn:uuid: prefix or missing dashes are all accepted.

  2. 2

    Read the version and variant, and the creation date when the version stores one.

  3. 3

    Scan the detail rows for the raw timestamp ticks, clock sequence and node or MAC address.

  4. 4

    Copy the summary, or grab any of the alternative forms: canonical, raw hex, Base64, URN or Microsoft GUID.

About the UUID Decoder

The ByteTools UUID Decoder breaks a UUID down into the parts the specification defines. It validates the 8-4-4-4-12 layout, reads the version nibble and the RFC 4122 variant bits, and then decodes whatever else that version carries — for version 1 and 6 that is a 60-bit Gregorian timestamp, a clock sequence and a node identifier, and for version 7 a leading Unix-millisecond timestamp.

Timestamps are converted for you: the 100-nanosecond Gregorian count is divided down and shifted by the 12,219,292,800,000 millisecond gap between 1582 and the Unix epoch, so you get an ordinary date in both UTC and your local time zone. The tool also tells you when a version simply has no timestamp, as with random version 4 UUIDs.

Everything is computed 100% locally in your browser and nothing is uploaded. UUIDs frequently identify real records and real people, so they are worth keeping off third-party servers as a matter of habit. Alongside the decoded fields you also get the same identifier in every common form: canonical, raw hex, Base64, URN and the Microsoft braced GUID.

Frequently asked questions

How do I find out when a UUID was created?

Only some versions store a time. Version 1 and version 6 embed a 60-bit count of 100-nanosecond intervals since 15 October 1582, and version 7 embeds a plain Unix-millisecond timestamp. Paste the UUID and this tool converts whichever one applies into a readable date. Version 4 UUIDs are purely random and hold no time at all.

How do I tell which version a UUID is?

The first character of the third group is the version digit. In 017f22e2-79b0-7cc3-98c4-dc0c0c07398f that digit is 7, so it is a version 7 UUID. This tool reads it for you and also checks the variant bits at the start of the fourth group, which confirm it follows the RFC layout.

Does a version 1 UUID really contain a MAC address?

Often, yes. The last 12 hex digits are the node field, which the original specification says should be the machine's network card address. That is a genuine privacy concern, so many implementations set the multicast bit and use random bytes instead. This tool tells you which of the two you are looking at.

What is the difference between UUID v4 and v7?

Version 4 is entirely random, which makes it unguessable but poor as a database primary key because inserts land all over the index. Version 7 puts a millisecond timestamp in the leading bits, so IDs sort by creation time and insert sequentially, while the remaining bits stay random.

Is my UUID sent anywhere when I decode it?

No. The parsing is pure JavaScript running in your browser and the page makes no network calls, so identifiers tied to real customer records stay private.

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