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)

019c8e8a-b10e-7fe8-9dd2-399c8fe581bd
019c8e8a-b10f-7182-9147-e8d133c530a7
019c8e8a-b10f-72bd-a3bd-67b1ef22c826
019c8e8a-b10f-73e0-b87c-9f4907b7a123
019c8e8a-b10f-74fa-a611-13b6483ccb66
019c8e8a-b10f-7611-ad0d-2aab408aba53
019c8e8a-b10f-7727-9933-bdec87bbf279
019c8e8a-b10f-783e-8e02-3231b328272a
019c8e8a-b10f-7959-ba19-0472539f0a7f
019c8e8a-b10f-7a73-b4fa-e90ba8641203
019c8e8a-b10f-7b8e-b91d-764ddb9b1134
019c8e8a-b10f-7ca4-9a56-b744f08b3196
019c8e8a-b10f-7dbf-a3ce-0e983042df30
019c8e8a-b10f-7ed5-a97c-43d33b71fdb1
019c8e8a-b10f-7fec-92c3-74cbd958f3d3

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)

1f111521-d25c-64ac-9e44-4cf95d479851
1f111521-d25c-6646-9e44-4cf95d479851
1f111521-d25c-672c-9e44-4cf95d479851
1f111521-d25c-67fe-9e44-4cf95d479851
1f111521-d25c-68bc-9e44-4cf95d479851
1f111521-d25c-697a-9e44-4cf95d479851
1f111521-d25c-6a38-9e44-4cf95d479851
1f111521-d25c-6af6-9e44-4cf95d479851
1f111521-d25c-6baa-9e44-4cf95d479851
1f111521-d25c-6c68-9e44-4cf95d479851
1f111521-d25c-6db2-9e44-4cf95d479851
1f111521-d25c-6e7a-9e44-4cf95d479851
1f111521-d25c-6f42-9e44-4cf95d479851
1f111521-d25d-600a-9e44-4cf95d479851
1f111521-d25d-60be-9e44-4cf95d479851

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)

6752fce6-731a-40fa-8f61-309435a00efc
7e303c22-e67e-453c-945c-bb4f3075d615
bbb9eae5-618a-4954-8397-5cb6213ea0c4
9e2977f0-41aa-4a35-b05d-58304c77b998
a4764ef3-1fd5-4714-8450-fafe0e31b179
906c13fe-20a7-4672-80d3-747d688bd6a6
d1652681-1254-4915-9516-b99d3bed30c3
cad2d0a5-0c94-4fd1-be1f-31654feb6e03
8695fc6c-c2de-44ed-9b68-a51676368050
9fd07532-2d07-4783-84b2-b03ccc744e6e
8ab7cdc7-d7c3-476f-a393-5830de806f87
dd539240-60b7-4bdd-ae7c-adcf12f5ff7f
b6fe3d97-5a9e-4c61-989d-f20c426d1319
69bdf945-d674-4174-abb2-ef6b035767fe
4986e45f-238d-4448-bbd9-4cd9ef8bdba9

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)

1d25d604-1152-11f1-9e44-4cf95d479851
1d25d672-1152-11f1-9e44-4cf95d479851
1d25d6d6-1152-11f1-9e44-4cf95d479851
1d25d73a-1152-11f1-9e44-4cf95d479851
1d25d79e-1152-11f1-9e44-4cf95d479851
1d25d7f8-1152-11f1-9e44-4cf95d479851
1d25d85c-1152-11f1-9e44-4cf95d479851
1d25d8b6-1152-11f1-9e44-4cf95d479851
1d25d91a-1152-11f1-9e44-4cf95d479851
1d25d97e-1152-11f1-9e44-4cf95d479851
1d25d9e2-1152-11f1-9e44-4cf95d479851
1d25da46-1152-11f1-9e44-4cf95d479851
1d25daa0-1152-11f1-9e44-4cf95d479851
1d25db04-1152-11f1-9e44-4cf95d479851
1d25db5e-1152-11f1-9e44-4cf95d479851

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)

16a8eb13-bf01-8703-87ea-5ce32bd83b97
e885ec13-bf01-8703-87ea-5ce32bd83b97
8036ed13-bf01-8703-87ea-5ce32bd83b97
06ceee13-bf01-8703-87ea-5ce32bd83b97
c1a8ef13-bf01-8703-87ea-5ce32bd83b97
9b05f013-bf01-8703-87ea-5ce32bd83b97
d00bf113-bf01-8703-87ea-5ce32bd83b97
1d7cf213-bf01-8703-87ea-5ce32bd83b97
19aff313-bf01-8703-87ea-5ce32bd83b97
5fbef413-bf01-8703-87ea-5ce32bd83b97
cd12f513-bf01-8703-87ea-5ce32bd83b97
ec63f613-bf01-8703-87ea-5ce32bd83b97
6653f713-bf01-8703-87ea-5ce32bd83b97
ff66f813-bf01-8703-87ea-5ce32bd83b97
07e6fa13-bf01-8703-87ea-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: