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)

019ddb7d-280d-7534-be56-a25fff12fc6a
019ddb7d-280d-770b-bd8f-c8b22c0979d0
019ddb7d-280d-7884-b948-5092d6b4d6ef
019ddb7d-280d-79e4-a20c-52d05922a832
019ddb7d-280d-7b44-b74a-bcc31c3847bd
019ddb7d-280d-7c90-8432-814f1c14a886
019ddb7d-280d-7dd8-9416-d1a59e1536e5
019ddb7d-280d-7f2c-8db4-3549e304ef8c
019ddb7d-280e-7077-8bfc-9fe9544ed398
019ddb7d-280e-71c3-96c5-eb68810dd4e7
019ddb7d-280e-730b-bcce-2fb2d6d0e30e
019ddb7d-280e-745f-8d26-67aa25275c0f
019ddb7d-280e-75b7-9bff-6ca367fb1d7d
019ddb7d-280e-770b-8124-4808eb2ff8e6
019ddb7d-280e-7857-bb1e-c3671345d8c3

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)

1f1441fd-c6df-6d48-8f62-4cf95d479851
1f1441fd-c6df-6f8c-8f62-4cf95d479851
1f1441fd-c6e0-6108-8f62-4cf95d479851
1f1441fd-c6e0-6270-8f62-4cf95d479851
1f1441fd-c6e0-63ce-8f62-4cf95d479851
1f1441fd-c6e0-6522-8f62-4cf95d479851
1f1441fd-c6e0-668a-8f62-4cf95d479851
1f1441fd-c6e0-67de-8f62-4cf95d479851
1f1441fd-c6e0-6932-8f62-4cf95d479851
1f1441fd-c6e0-6a86-8f62-4cf95d479851
1f1441fd-c6e0-6c98-8f62-4cf95d479851
1f1441fd-c6e0-6e00-8f62-4cf95d479851
1f1441fd-c6e0-6f68-8f62-4cf95d479851
1f1441fd-c6e1-60d0-8f62-4cf95d479851
1f1441fd-c6e1-6224-8f62-4cf95d479851

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)

03f01854-0ced-43d7-ade4-793c9d2f32e6
c0609d89-fc5f-42d6-b799-497e17563208
b0188233-116d-4c34-9fb1-55b6ce2e2313
d43ac6c0-f1ae-4468-8928-12b7c072faef
afdeedad-6d8a-4f1d-a9c2-b3690aa9f19b
863f92ae-f0b0-463f-bbea-4cffde10043a
c0de800e-0a3e-4e5b-a881-07930626f024
8b8749a5-49a9-4415-b861-923ecb32b4e0
5d523c3f-f28d-47f7-8947-67ce94dd7352
7d0e8f9e-83ea-4ccf-8a06-8b51f38eb3a1
a806806b-0074-417d-807f-1a5851ec7616
9771fd9a-d90a-40a5-9ddf-40132e1e793b
40937f4f-73e0-4ea0-aa01-fcc8781bbcbb
d49ee38a-3da2-4f5a-9fce-f32e4bc66da6
84b0ba73-d6a0-4196-aecd-03b7b18a9b76

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)

dc6e1968-441f-11f1-8f62-4cf95d479851
dc6e1a08-441f-11f1-8f62-4cf95d479851
dc6e1aa8-441f-11f1-8f62-4cf95d479851
dc6e1b48-441f-11f1-8f62-4cf95d479851
dc6e1bde-441f-11f1-8f62-4cf95d479851
dc6e1c7e-441f-11f1-8f62-4cf95d479851
dc6e1d1e-441f-11f1-8f62-4cf95d479851
dc6e1dbe-441f-11f1-8f62-4cf95d479851
dc6e1e54-441f-11f1-8f62-4cf95d479851
dc6e1eea-441f-11f1-8f62-4cf95d479851
dc6e1f80-441f-11f1-8f62-4cf95d479851
dc6e200c-441f-11f1-8f62-4cf95d479851
dc6e20a2-441f-11f1-8f62-4cf95d479851
dc6e2138-441f-11f1-8f62-4cf95d479851
dc6e21d8-441f-11f1-8f62-4cf95d479851

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)

013ece05-6a05-8707-87ea-5ce32bd83b97
baa7cf05-6a05-8707-87ea-5ce32bd83b97
76cbd005-6a05-8707-87ea-5ce32bd83b97
2cfad105-6a05-8707-87ea-5ce32bd83b97
66c7d205-6a05-8707-87ea-5ce32bd83b97
a280d305-6a05-8707-87ea-5ce32bd83b97
f4a5d405-6a05-8707-87ea-5ce32bd83b97
406cd505-6a05-8707-87ea-5ce32bd83b97
46f3d605-6a05-8707-87ea-5ce32bd83b97
c366d705-6a05-8707-87ea-5ce32bd83b97
991bd805-6a05-8707-87ea-5ce32bd83b97
33eed905-6a05-8707-87ea-5ce32bd83b97
8710db05-6a05-8707-87ea-5ce32bd83b97
23a7dc05-6a05-8707-87ea-5ce32bd83b97
755fdd05-6a05-8707-87ea-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: