UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate random and/or time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate random (version 4) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate other UUID types
  • NCS (variant 0) UUID
  • Generate DCE Security (version 2) UUID
  • Generate name-based (version 3 / 5 / New: 8) UUID
  • New: Generate Custom (version 8) UUID
• Interpret a UUID
• Interpret a MAC address (MAC / EUI / ELI / SAI / AAI)
  • Generate an AAI

Generate random and/or time-based UUIDs

New: Generate Unix Epoch time-based (version 7) UUID ⭐

A UUIDv7 measures time in the Unix Epoch with an accuracy between 1ms and 245ns, depending on how many bits are spent for the timestamp (48-60 bits). The rest of the UUID (62-74 bits) is filled with random data. The timestamp is at the front of the UUID, therefore the UUIDs are monotonically increasing, which is good for using them in database indexes. Since this UUID version does not contain a MAC address, it is also recommended due to the improved privacy.

Show format

Variant 1, Version 7 UUID:
- 48 bit Unix Time in milliseconds
-  4 bit Version (fix 0x7)
- 12 bit Data
-  2 bit Variant (fix 0b10)
- 62 bit Data

Structure of data (74 bits):
- OPTIONAL : Sub-millisecond timestamp fraction (0-12 bits)
- OPTIONAL : Carefully seeded counter
- Random generated bits for any remaining space

Time resolution for various sub-millisecond bits:
0 bits fraction = 1 ms
1 bits fraction = 500 µs
2 bits fraction = 250 µs
3 bits fraction = 125 µs
4 bits fraction = 62.5 µs
5 bits fraction = 31.25 µs
6 bits fraction = 15.625 µs
7 bits fraction = 7.8125 µs
8 bits fraction = 3.90625 µs
9 bits fraction = 1.953125 µs
10 bits fraction = 976.5625 ns
11 bits fraction = 488.28125 ns
12 bits fraction = 244.140625 ns

This implementation outputs:
- 12 bits sub-millisecond timestamp (~245ns resolution)
- no counter
- 62 bits random data

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

019b5bcd-fe31-7c52-bae0-bdda013f945a
019b5bcd-fe31-7df8-8c18-2f69adccc177
019b5bcd-fe31-7f3c-b678-81d12eacb709
019b5bcd-fe32-7073-9cff-2cf3e78daf9d
019b5bcd-fe32-7196-9433-bbdb43fd821b
019b5bcd-fe32-72b1-8f98-229ae24cee0a
019b5bcd-fe32-73cf-8a80-ecf0ec506c5a
019b5bcd-fe32-74ea-b4d6-b33d44aea27b
019b5bcd-fe32-7600-80b5-9f152e2ef428
019b5bcd-fe32-771b-80e9-dddf16c6f1af
019b5bcd-fe32-783a-bfcc-64ba45d22ebf
019b5bcd-fe32-7954-9448-7d01f2985535
019b5bcd-fe32-7a73-b6f7-68bad60bfb6e
019b5bcd-fe32-7b8a-914c-820560d66f95
019b5bcd-fe32-7ca4-965f-7308ec4b71a8

New: Generate reordered Gregorian time-based (version 6) UUID ⏰

Like UUIDv1, this kind of UUID is made of the MAC address of the generating computer, the time, and a clock sequence. However, the components in UUIDv6 are reordered (time is at the beginning), so that UUIDs are monotonically increasing, which is good for using them in database indexes.

Show format

Variant 1, Version 6 UUID:
- 48 bit High Time
-  4 bit Version (fix 0x6)
- 12 bit Low Time
-  2 bit Variant (fix 0b10)
-  6 bit Clock Sequence High
-  8 bit Clock Sequence Low
- 48 bit MAC Address

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

1f0e2843-21ae-63da-ac3f-4cf95d479851
1f0e2843-21ae-656a-ac3f-4cf95d479851
1f0e2843-21ae-6650-ac3f-4cf95d479851
1f0e2843-21ae-6722-ac3f-4cf95d479851
1f0e2843-21ae-67ea-ac3f-4cf95d479851
1f0e2843-21ae-68b2-ac3f-4cf95d479851
1f0e2843-21ae-6984-ac3f-4cf95d479851
1f0e2843-21ae-6a4c-ac3f-4cf95d479851
1f0e2843-21ae-6b0a-ac3f-4cf95d479851
1f0e2843-21ae-6bd2-ac3f-4cf95d479851
1f0e2843-21ae-6d12-ac3f-4cf95d479851
1f0e2843-21ae-6de4-ac3f-4cf95d479851
1f0e2843-21ae-6eac-ac3f-4cf95d479851
1f0e2843-21ae-6f74-ac3f-4cf95d479851
1f0e2843-21af-603c-ac3f-4cf95d479851

Generate random (version 4) UUID 🎲

A UUIDv4 is made of 122 random bits. No other information is encoded in this kind of UUID.

Show format

Variant 1, Version 4 UUID:
- 48 bit Random High
-  4 bit Version (fix 0x4)
- 12 bit Random Mid
-  2 bit Variant (fix 0b10)
- 62 bit Random Low

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

873bf198-7259-46fc-9d21-8a7e98772c93
84b6ef81-76b1-46d9-82e8-9875fad2e181
8b32925c-f129-4b6f-a539-9f5306052844
1f4f5097-cdd5-468f-ba67-5fdffe2ef61f
ff0bba4f-db77-46f9-bfdc-62944c491ca1
761fcd4a-0b9d-4f7c-9ed6-3fc19d97fd38
05992d7a-27a8-4d36-aada-63e7e96cda6e
cd8c1722-443b-42de-af6f-706a4c494296
50e3144a-1162-493b-8a6e-604dcb67bdf2
08d2bd50-9dac-4145-a7c2-b12004b8a6c4
7235d426-fcb9-4e4a-8bb8-e69b43e754d4
0edf1d43-7f37-44e1-9c36-54307885295b
9669a8a2-a315-4011-9c7f-a860a6b33a5b
c3aeea90-3376-4fad-a328-2b5773fcaf22
68ac9468-232d-43b7-9082-667f562d31ac

Generate Gregorian time-based (version 1) UUID ⏰

A UUIDv1 is made of the MAC address of the generating computer, the time, and a clock sequence.

Show format

Variant 1, Version 1 UUID:
- 32 bit Low Time
- 16 bit Mid Time
-  4 bit Version (fix 0x1)
- 12 bit High Time
-  2 bit Variant (fix 0b10)
-  6 bit Clock Sequence High
-  8 bit Clock Sequence Low
- 48 bit MAC Address

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

321af564-e284-11f0-ac3f-4cf95d479851
321af5c8-e284-11f0-ac3f-4cf95d479851
321af62c-e284-11f0-ac3f-4cf95d479851
321af690-e284-11f0-ac3f-4cf95d479851
321af6fe-e284-11f0-ac3f-4cf95d479851
321af762-e284-11f0-ac3f-4cf95d479851
321af7da-e284-11f0-ac3f-4cf95d479851
321af83e-e284-11f0-ac3f-4cf95d479851
321af898-e284-11f0-ac3f-4cf95d479851
321af8fc-e284-11f0-ac3f-4cf95d479851
321af960-e284-11f0-ac3f-4cf95d479851
321af9c4-e284-11f0-ac3f-4cf95d479851
321afa28-e284-11f0-ac3f-4cf95d479851
321afa8c-e284-11f0-ac3f-4cf95d479851
321afaf0-e284-11f0-ac3f-4cf95d479851

Generate SQL Server sortable time-based (version 8) UUID

The sorting of UUIDs in SQL Server is rather confusing and incompatible with UUIDv6 and UUIDv7.
Therefore this method developed by HickelSOFT generates UUIDs which are sortable by SQL Server.
They have a time resolution of 1 milliseconds combined with 16 bits of random data.
C# implementation | PHP implementation

Show format

Version 3: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 compliant:
- 16 bit Random data
-  8 bit UTC Milliseconds transformed from 1000ms to 0..255, deviation -2ms..2ms (hex encoded)
-  8 bit UTC Seconds (hex encoded)
- 16 bit UTC Minute of the day (1..1440, hex encoded) LITTLE ENDIAN (CD AB = 0xABCD)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded) LITTLE ENDIAN (8C AB = 0xABC)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 48 bit Signature 0x5ce32bd83b97

Version 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 compliant:
- 16 bit Random data
-  8 bit UTC Milliseconds transformed from 1000ms to 0..255, deviation -2ms..2ms (hex encoded)
-  8 bit UTC Seconds (hex encoded)
- 16 bit UTC Minute of the day (1..1440, hex encoded) BIG ENDIAN (AB CD = 0xABCD) = WRONG!!!
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded) BIG ENDIAN (8A BC = 0xABC) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 48 bit Signature 0x5ce32bd83b96

Version 1: Resolution of 1 milliseconds, random part of 16 bits, local timezone, 48 zero bits "signature", *NOT* UUIDv8 compliant:
- 16 bit Random data
-  8 bit Generator's local timezone Milliseconds transformed from 1000ms to 0..255, deviation -4ms..0ms (hex encoded)
-  8 bit Generator's local timezone Seconds (BCD encoded)
-  8 bit Generator's local timezone Minute (BCD encoded)
-  8 bit Generator's local timezone Hour (BCD encoded)
-  8 bit Generator's local timezone Day (BCD encoded)
-  8 bit Generator's local timezone Month (BCD encoded)
-  8 bit Generator's local timezone 2-digit year (BCD encoded)
-  8 bit Generator's local timezone 2-digit century (BCD encoded)
- 48 bit Signature 0x000000000000

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

21b04419-3504-8816-87e9-5ce32bd83b97
57f34519-3504-8816-87e9-5ce32bd83b97
58414619-3504-8816-87e9-5ce32bd83b97
a8544719-3504-8816-87e9-5ce32bd83b97
14a14819-3504-8816-87e9-5ce32bd83b97
7e104919-3504-8816-87e9-5ce32bd83b97
ef7c4a19-3504-8816-87e9-5ce32bd83b97
83204c19-3504-8816-87e9-5ce32bd83b97
8e934d19-3504-8816-87e9-5ce32bd83b97
c7fb4e19-3504-8816-87e9-5ce32bd83b97
73f34f19-3504-8816-87e9-5ce32bd83b97
93bc5019-3504-8816-87e9-5ce32bd83b97
66ca5119-3504-8816-87e9-5ce32bd83b97
05e15219-3504-8816-87e9-5ce32bd83b97
62bf5319-3504-8816-87e9-5ce32bd83b97

Generate other UUID types

The following types of UUIDs are less common and/or require special knowledge. Please only use the following generators if you know what you are doing.

NCS (variant 0) UUID

The NCS UUIDs are a legacy format initially designed by Apollo Computer that cannot be generated anymore, because the amount of available timestamp bits was exhausted on 5 September 2015. As an example, here is the last possible NCS UUID (all bits of the timestamp are set to 1) for IP address 127.0.0.1: ffffffff-ffff-0000-027f-000001000000.

Show format

Variant 0 UUID:
- 32 bit High Time
- 16 bit Low Time
- 16 bit Reserved
-  1 bit Variant (fix 0b0)
-  7 bit Family
- 56 bit Node

Generate DCE Security (version 2) UUID

A UUIDv2 contains information about the creator (person, group, or organization), the generating system (MAC address), and time. The creator information replaced parts of the time bits, therefore the time resolution is very low.

Show format

Variant 1, Version 2 UUID:
- 32 bit Local Domain Number
- 16 bit Mid Time
-  4 bit Version (fix 0x2)
- 12 bit High Time
-  2 bit Variant (fix 0b10)
-  6 bit Clock Sequence
-  8 bit Local Domain
- 48 bit MAC Address

Generate name-based (version 3 / 5 / New: 8) UUID

A UUIDv3 is made out of a MD5 hash and a UUIDv5 is made out of a SHA1 hash. RFC 9562 also contains an example for a custom UUIDv8 implementation that uses modern hash algorithms.

Show format

Variant 1, Version 3/5/8 UUID:
- 48 bit Hash High
-  4 bit Version (fix 0x3, 0x5, or 0x8)
- 12 bit Hash Mid
-  2 bit Variant (fix 0b10)
- 62 bit Hash Low


As shown in RFC 9562 Appendix B.2:
UUIDv8(HashAlgo, NameSpaceUuid, Data) := ConvertRawBytesToUuid_v8(HashAlgo( Binary[NameSpaceUuid] || Data )).

New: Generate Custom (version 8) UUID

UUIDv8 is made of 122 bits application-specific / custom data. The other 6 bits are used to specify the variant and version of the UUID, to make it RFC-compatible.

Show format

Variant 1, Version 8 UUID:
- 48 bit Custom data [Block 1+2]
-  4 bit Version (fix 0x8)
- 12 bit Custom data [Block 3]
-  2 bit Variant (fix 0b10)
- 62 bit Custom data [Block 4+5]

Interpret a UUID

You can enter a UUID in the following notations:

• Classic notation (case insensitive, curly braces optional): 9e83839a-5967-11e4-8c1c-78e3b5fc7f22
• As OID: 2.25.210700883446948645633376489934419689250

The script will output:

• Notation as UUID and OID
• Version, variant, and additional data (date and time, clock sequence, node id, etc.)

Please enter a UUID or UUID OID:

Interpret a MAC address (MAC / EUI / ELI / SAI / AAI)

You can enter a UUID in the following notations:

• AA-BB-CC-DD-EE-FF
• AA:BB:CC:DD:EE:FF
• AABBCC.DDEEFF (case insensitive)
• AA-BB-CC-DD-EE-FF-11-22 (EUI-64)
• AA:BB:CC:DD:EE:FF-11-22 (EUI-64)
• fe80::1322:33ff:fe44:5566 (IPv6 Link Local / EUI-64)

The script will output:

• Information about the I/G and U/L flags.
• Information about the entry in the IEEE registry, if available.
• Information about the registrant, if available.

Please enter a MAC (EUI, ELI, SAI, AAI), or IPv6-Link-Local address:

Generate an AAI

An Administratively Assigned Identifier (AAI) is a MAC address which can be locally defined by applications or an administrator. Unlike the EUI, an AAI is NOT worldwide unique.

The following options are rather unusual, but are implemented for the sake of completeness: