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)

019c8e13-e3b1-785b-93f1-d2beff9f55a3
019c8e13-e3b1-7a8c-9df9-bdd99d56d774
019c8e13-e3b1-7c0d-a433-64e5c120db03
019c8e13-e3b1-7d34-b182-010dfd79f981
019c8e13-e3b1-7e52-ae3c-23930fad1f98
019c8e13-e3b1-7f6d-a7a0-ceec782dfa84
019c8e13-e3b2-7088-94d6-cb314af55135
019c8e13-e3b2-719e-b20e-d4347b98b60e
019c8e13-e3b2-72b9-81e4-e54b26672aa6
019c8e13-e3b2-73d3-b8d5-12e7f73cb1ac
019c8e13-e3b2-74ee-ad72-149fc3724658
019c8e13-e3b2-766b-8e84-653e63754b76
019c8e13-e3b2-778e-a6a3-c016f8e4f3f0
019c8e13-e3b2-78ad-b04d-d8b7144054bb
019c8e13-e3b2-79c7-b25c-a07a278aa51b

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)

1f1113ff-c6fb-670c-9e44-4cf95d479851
1f1113ff-c6fb-68c4-9e44-4cf95d479851
1f1113ff-c6fb-69aa-9e44-4cf95d479851
1f1113ff-c6fb-6a72-9e44-4cf95d479851
1f1113ff-c6fb-6b30-9e44-4cf95d479851
1f1113ff-c6fb-6bee-9e44-4cf95d479851
1f1113ff-c6fb-6cac-9e44-4cf95d479851
1f1113ff-c6fb-6d60-9e44-4cf95d479851
1f1113ff-c6fb-6e1e-9e44-4cf95d479851
1f1113ff-c6fb-6edc-9e44-4cf95d479851
1f1113ff-c6fc-6008-9e44-4cf95d479851
1f1113ff-c6fc-60da-9e44-4cf95d479851
1f1113ff-c6fc-6198-9e44-4cf95d479851
1f1113ff-c6fc-624c-9e44-4cf95d479851
1f1113ff-c6fc-630a-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)

9fef1378-d7e7-45ea-b9d7-602795aebed2
3ca77cc7-4a57-4e9d-8f84-f8976ef6aeb6
47d75c6d-66db-4b3e-911c-2ada9c31478d
60ffa801-a23e-44a1-8b02-83da4d587ee1
2d6a216e-73e3-4137-859c-0829380d8dbe
a91319da-170e-45e3-912a-de3340758427
73619c13-4259-4116-af5c-551febca801a
491a3615-0dd8-46b8-8097-28770e007f68
bd911a0a-ec0a-4940-bd9d-6e55e3cce5b3
75f8f0fb-7a78-4065-a17f-a7b1612ff9ae
1bff532c-95cc-45da-88e6-0bc18d25cf90
f66c282c-bddf-43e7-970c-90eff60618e3
f310b029-1743-4362-bdab-d5cad06b4bcd
b1070f78-0b24-40f7-b809-d3e52f3e5927
688b7d9a-a10e-4581-93c6-5a3baefc2ba3

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)

fc6fc83c-113f-11f1-9e44-4cf95d479851
fc6fc8a0-113f-11f1-9e44-4cf95d479851
fc6fc904-113f-11f1-9e44-4cf95d479851
fc6fc968-113f-11f1-9e44-4cf95d479851
fc6fc9cc-113f-11f1-9e44-4cf95d479851
fc6fca26-113f-11f1-9e44-4cf95d479851
fc6fca80-113f-11f1-9e44-4cf95d479851
fc6fcae4-113f-11f1-9e44-4cf95d479851
fc6fcb48-113f-11f1-9e44-4cf95d479851
fc6fcba2-113f-11f1-9e44-4cf95d479851
fc6fcc06-113f-11f1-9e44-4cf95d479851
fc6fcc60-113f-11f1-9e44-4cf95d479851
fc6fccba-113f-11f1-9e44-4cf95d479851
fc6fcd14-113f-11f1-9e44-4cf95d479851
fc6fcd78-113f-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)

912d1922-3d01-8703-87ea-5ce32bd83b97
9aa01a22-3d01-8703-87ea-5ce32bd83b97
10ab1b22-3d01-8703-87ea-5ce32bd83b97
05c71c22-3d01-8703-87ea-5ce32bd83b97
ad641d22-3d01-8703-87ea-5ce32bd83b97
ff051e22-3d01-8703-87ea-5ce32bd83b97
5b621f22-3d01-8703-87ea-5ce32bd83b97
92822022-3d01-8703-87ea-5ce32bd83b97
56c92222-3d01-8703-87ea-5ce32bd83b97
efa92322-3d01-8703-87ea-5ce32bd83b97
2d352422-3d01-8703-87ea-5ce32bd83b97
c98a2522-3d01-8703-87ea-5ce32bd83b97
1dfd2622-3d01-8703-87ea-5ce32bd83b97
4d672722-3d01-8703-87ea-5ce32bd83b97
fcde2822-3d01-8703-87ea-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: