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)

019b97d1-ce52-7825-8811-48d2c880187d
019b97d1-ce52-79e0-9339-426eb8accc3a
019b97d1-ce52-7b23-9dae-92dbf82e6b87
019b97d1-ce52-7c42-b776-50411b551756
019b97d1-ce52-7d61-98e1-6b085aba853a
019b97d1-ce52-7e7f-abdf-873f84d19cde
019b97d1-ce52-7f9a-b007-76613476e6dd
019b97d1-ce53-70b5-98ac-53db53b6b9fe
019b97d1-ce53-71cf-98c7-f627f0512bd5
019b97d1-ce53-72ea-b39b-cfa245827455
019b97d1-ce53-7409-a1a6-c05b1f9a7d74
019b97d1-ce53-7527-9c5a-1cbf32a970ec
019b97d1-ce53-7642-87bb-c652db171d4f
019b97d1-ce53-775d-920f-6407daa376fa
019b97d1-ce53-7873-aa34-abb937455e2f

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)

1f0ebac8-70ce-64a2-9b84-4cf95d479851
1f0ebac8-70ce-6664-9b84-4cf95d479851
1f0ebac8-70ce-674a-9b84-4cf95d479851
1f0ebac8-70ce-6812-9b84-4cf95d479851
1f0ebac8-70ce-68da-9b84-4cf95d479851
1f0ebac8-70ce-6998-9b84-4cf95d479851
1f0ebac8-70ce-6a56-9b84-4cf95d479851
1f0ebac8-70ce-6b14-9b84-4cf95d479851
1f0ebac8-70ce-6bd2-9b84-4cf95d479851
1f0ebac8-70ce-6c86-9b84-4cf95d479851
1f0ebac8-70ce-6dc6-9b84-4cf95d479851
1f0ebac8-70ce-6e8e-9b84-4cf95d479851
1f0ebac8-70ce-6f4c-9b84-4cf95d479851
1f0ebac8-70cf-600a-9b84-4cf95d479851
1f0ebac8-70cf-60c8-9b84-4cf95d479851

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)

f81e7402-ae46-41c3-a83f-639f7e29b841
ba36e236-b94c-4283-bfe6-4674b51c18d2
ba0449b4-0bbb-4290-9085-8af2b467e54a
5c841c1c-44bf-490d-9daa-f3fae7ab1d7f
82b89e2e-d334-4ab5-a36c-f8d8a29d6cf3
e414593a-a2a8-414b-9528-85e42374e76e
36f552e7-e603-46d8-b2f8-d32e54a17b39
9c809005-fb80-422c-bbb9-3562a03033e3
60eff8c8-e82e-4944-b6da-65f2a5e23cf6
e527d576-b5e0-439d-a49c-b921f7ed45a3
acc632e4-b9df-4d85-8799-8d583d634ae0
de79bac6-2190-44a3-addb-e8816fc0c2d8
13862435-b187-4e30-bab0-0ac5805c3f0e
7e314c86-c902-4542-a1cd-09d14e22d956
470a1ec8-ab8a-40d7-b809-d257c11e3da1

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)

870cf5f0-ebac-11f0-9b84-4cf95d479851
870cf654-ebac-11f0-9b84-4cf95d479851
870cf6b8-ebac-11f0-9b84-4cf95d479851
870cf712-ebac-11f0-9b84-4cf95d479851
870cf776-ebac-11f0-9b84-4cf95d479851
870cf7c6-ebac-11f0-9b84-4cf95d479851
870cf82a-ebac-11f0-9b84-4cf95d479851
870cf884-ebac-11f0-9b84-4cf95d479851
870cf8de-ebac-11f0-9b84-4cf95d479851
870cf94c-ebac-11f0-9b84-4cf95d479851
870cf9a6-ebac-11f0-9b84-4cf95d479851
870cfa00-ebac-11f0-9b84-4cf95d479851
870cfa5a-ebac-11f0-9b84-4cf95d479851
870cfab4-ebac-11f0-9b84-4cf95d479851
870cfb18-ebac-11f0-9b84-4cf95d479851

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)

40d31e30-4202-8700-87ea-5ce32bd83b97
e8ba1f30-4202-8700-87ea-5ce32bd83b97
9abd2030-4202-8700-87ea-5ce32bd83b97
f43e2130-4202-8700-87ea-5ce32bd83b97
93802230-4202-8700-87ea-5ce32bd83b97
972d2330-4202-8700-87ea-5ce32bd83b97
66032430-4202-8700-87ea-5ce32bd83b97
69032530-4202-8700-87ea-5ce32bd83b97
c76a2630-4202-8700-87ea-5ce32bd83b97
fb612730-4202-8700-87ea-5ce32bd83b97
e4b42830-4202-8700-87ea-5ce32bd83b97
05882930-4202-8700-87ea-5ce32bd83b97
a49d2a30-4202-8700-87ea-5ce32bd83b97
07452b30-4202-8700-87ea-5ce32bd83b97
e2b92c30-4202-8700-87ea-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: