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)

0196b4c2-93dc-7917-b28d-06c0026b2906
0196b4c2-93dc-7aa4-8f24-7d5a1e565efe
0196b4c2-93dc-7be8-a615-a8fef52a23f8
0196b4c2-93dc-7d13-b93a-5771a7ef1739
0196b4c2-93dc-7e36-ba3a-fac63c0902b8
0196b4c2-93dc-7f50-8d64-0c9cd88dbb57
0196b4c2-93dd-706b-bdb0-1435a421851b
0196b4c2-93dd-7186-afaf-e460e1eb658b
0196b4c2-93dd-72a0-9502-809328b9d0cc
0196b4c2-93dd-73bb-8408-c9201ada1c11
0196b4c2-93dd-74d5-81f2-48175d9e65be
0196b4c2-93dd-75ec-9727-4698e0d43dd7
0196b4c2-93dd-7707-b19c-31d344f07f5b
0196b4c2-93dd-7825-8994-5153975503aa
0196b4c2-93dd-7940-a3aa-75a774b92619

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)

1f02cc70-4314-6338-aa53-4cf95d479851
1f02cc70-4314-64c8-aa53-4cf95d479851
1f02cc70-4314-65b8-aa53-4cf95d479851
1f02cc70-4314-6680-aa53-4cf95d479851
1f02cc70-4314-6752-aa53-4cf95d479851
1f02cc70-4314-681a-aa53-4cf95d479851
1f02cc70-4314-68e2-aa53-4cf95d479851
1f02cc70-4314-69aa-aa53-4cf95d479851
1f02cc70-4314-6a72-aa53-4cf95d479851
1f02cc70-4314-6b3a-aa53-4cf95d479851
1f02cc70-4314-6c84-aa53-4cf95d479851
1f02cc70-4314-6d56-aa53-4cf95d479851
1f02cc70-4314-6e1e-aa53-4cf95d479851
1f02cc70-4314-6ee6-aa53-4cf95d479851
1f02cc70-4314-6fae-aa53-4cf95d479851

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)

6582d6ab-b056-4797-86cb-99699d6ae749
3b82dc45-d073-4c71-889e-2505eeb0c4d5
dae62f7d-4a72-4c82-845c-819478fc2cb6
30d91273-b75e-4595-8cda-42abf1bb869b
d899d512-ff86-4789-be6e-263255ab79e3
9d9f2ad7-4974-4040-9ce6-08402aa0a53c
78643b15-2dde-4b5f-9cf8-d4a04aefa096
d91bcab1-4f79-44f2-b2dc-fcc705b88c36
630cccb7-aca4-409c-896d-529c7207032b
3cf7f12c-eb89-48d9-845f-c3b59914fcb1
6fc02518-54b5-4145-92fd-f02eabeb28ac
78ffd8ab-381a-4bf3-9c37-5ee3d4e2d0a0
9a77151b-ebaf-48f9-9f91-ecb257a5eca6
9c36540c-cd92-4806-b0af-ef2c85bc8725
0f38a40a-a5b7-45f3-851d-c67b96b3e4b3

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)

043154c2-2cc7-11f0-aa53-4cf95d479851
04315526-2cc7-11f0-aa53-4cf95d479851
0431558a-2cc7-11f0-aa53-4cf95d479851
043155e4-2cc7-11f0-aa53-4cf95d479851
04315648-2cc7-11f0-aa53-4cf95d479851
043156ac-2cc7-11f0-aa53-4cf95d479851
04315706-2cc7-11f0-aa53-4cf95d479851
0431576a-2cc7-11f0-aa53-4cf95d479851
043157c4-2cc7-11f0-aa53-4cf95d479851
04315828-2cc7-11f0-aa53-4cf95d479851
04315918-2cc7-11f0-aa53-4cf95d479851
0431597c-2cc7-11f0-aa53-4cf95d479851
043159ea-2cc7-11f0-aa53-4cf95d479851
04315a44-2cc7-11f0-aa53-4cf95d479851
04315aa8-2cc7-11f0-aa53-4cf95d479851

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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

0d08e40c-02a5-8081-87e9-5ce32bd83b96
971fe50c-02a5-8081-87e9-5ce32bd83b96
6a01e60c-02a5-8081-87e9-5ce32bd83b96
d1b7e70c-02a5-8081-87e9-5ce32bd83b96
5495e80c-02a5-8081-87e9-5ce32bd83b96
6b97e90c-02a5-8081-87e9-5ce32bd83b96
8facea0c-02a5-8081-87e9-5ce32bd83b96
99e2eb0c-02a5-8081-87e9-5ce32bd83b96
459ced0c-02a5-8081-87e9-5ce32bd83b96
35aeee0c-02a5-8081-87e9-5ce32bd83b96
e6dcef0c-02a5-8081-87e9-5ce32bd83b96
313ff00c-02a5-8081-87e9-5ce32bd83b96
9d6ff10c-02a5-8081-87e9-5ce32bd83b96
90b9f20c-02a5-8081-87e9-5ce32bd83b96
a5a4f30c-02a5-8081-87e9-5ce32bd83b96

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: