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)

019b3eae-e957-7334-b946-dcd867654d6c
019b3eae-e957-74e2-b00d-be3cdcfa6309
019b3eae-e957-7625-ae35-c000cf66ae7a
019b3eae-e957-7748-b69b-6a34ae11ddde
019b3eae-e957-7867-aa3a-8ca726fb3bc7
019b3eae-e957-7982-8ae9-153b591fd571
019b3eae-e957-7a9c-95f2-663d0492a83b
019b3eae-e957-7b92-93bb-3e5558e326b1
019b3eae-e957-7cbd-bcd2-f2d836c1c39c
019b3eae-e957-7dd8-a167-5635cf2ae4b4
019b3eae-e957-7ef2-bd84-12b78d809fc5
019b3eae-e957-7009-bdfa-28db70e1853a
019b3eae-e958-7123-91b8-7b8ef8aee49b
019b3eae-e958-723a-b8a1-971484b12138
019b3eae-e958-7354-aaae-a92d1f53a1f1

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)

1f0de12a-3fc4-69a6-9bda-4cf95d479851
1f0de12a-3fc4-6b40-9bda-4cf95d479851
1f0de12a-3fc4-6c26-9bda-4cf95d479851
1f0de12a-3fc4-6d52-9bda-4cf95d479851
1f0de12a-3fc4-6e42-9bda-4cf95d479851
1f0de12a-3fc4-6f0a-9bda-4cf95d479851
1f0de12a-3fc4-6fd2-9bda-4cf95d479851
1f0de12a-3fc5-609a-9bda-4cf95d479851
1f0de12a-3fc5-6162-9bda-4cf95d479851
1f0de12a-3fc5-6220-9bda-4cf95d479851
1f0de12a-3fc5-6360-9bda-4cf95d479851
1f0de12a-3fc5-6432-9bda-4cf95d479851
1f0de12a-3fc5-64f0-9bda-4cf95d479851
1f0de12a-3fc5-65b8-9bda-4cf95d479851
1f0de12a-3fc5-6680-9bda-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)

d4a1a32b-e768-4038-b957-5ddda9991af1
4fb58b07-1d4b-4f08-b82b-926e0cc56154
6bf49b13-7fe0-420d-9216-acfa979bb353
d76329d6-8c47-49e5-9947-5f0e9e986239
1f85bc86-6ac2-4ce1-900f-ce8e734485fd
2c65860a-4888-41d9-9107-4dfb7e825927
c2d8e06a-76ad-45a3-a626-e5b91007a81a
629c5d40-226c-4289-b9a8-749ebc8974cf
fc41b1db-8acd-444e-9148-8fc20a21a08d
846f199b-4c5b-4d36-b20b-eee27094befc
cf843a84-3a6e-4f0d-9b76-bf3ab8915efa
6b0d68d4-f07e-4a58-887a-217d3cbdd5fa
260cd8de-dea4-41d3-a0d4-c484e6371659
3d81facf-71fd-4876-8ca4-0af4ac5de14f
bb0b47ad-b003-4b1c-bfce-8078ad06ad39

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)

a3fc5f9a-de12-11f0-9bda-4cf95d479851
a3fc6008-de12-11f0-9bda-4cf95d479851
a3fc606c-de12-11f0-9bda-4cf95d479851
a3fc60d0-de12-11f0-9bda-4cf95d479851
a3fc613e-de12-11f0-9bda-4cf95d479851
a3fc61a2-de12-11f0-9bda-4cf95d479851
a3fc6206-de12-11f0-9bda-4cf95d479851
a3fc6274-de12-11f0-9bda-4cf95d479851
a3fc62e2-de12-11f0-9bda-4cf95d479851
a3fc6346-de12-11f0-9bda-4cf95d479851
a3fc63aa-de12-11f0-9bda-4cf95d479851
a3fc640e-de12-11f0-9bda-4cf95d479851
a3fc64a4-de12-11f0-9bda-4cf95d479851
a3fc6512-de12-11f0-9bda-4cf95d479851
a3fc6576-de12-11f0-9bda-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)

b69e0d1d-8600-8316-87e9-5ce32bd83b97
555a0e1d-8600-8316-87e9-5ce32bd83b97
f89d0f1d-8600-8316-87e9-5ce32bd83b97
e01c101d-8600-8316-87e9-5ce32bd83b97
7b82111d-8600-8316-87e9-5ce32bd83b97
1cd2121d-8600-8316-87e9-5ce32bd83b97
2761131d-8600-8316-87e9-5ce32bd83b97
28ff141d-8600-8316-87e9-5ce32bd83b97
5583151d-8600-8316-87e9-5ce32bd83b97
0005161d-8600-8316-87e9-5ce32bd83b97
5966171d-8600-8316-87e9-5ce32bd83b97
800d181d-8600-8316-87e9-5ce32bd83b97
4d35191d-8600-8316-87e9-5ce32bd83b97
cd511a1d-8600-8316-87e9-5ce32bd83b97
c50f1b1d-8600-8316-87e9-5ce32bd83b97

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: