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)

019b3803-8b6d-7f0b-b7c9-a7a1acdc1efe
019b3803-8b6e-709c-a5f2-e03f4e3c3452
019b3803-8b6e-71e4-b015-a8aa81c1f7f5
019b3803-8b6e-7307-826a-5259deaf230d
019b3803-8b6e-741d-ad70-5b6cd94467a3
019b3803-8b6e-7538-b6a4-f65e8bb55add
019b3803-8b6e-7652-badf-736a39d65e54
019b3803-8b6e-776d-b00f-8b04b93d3524
019b3803-8b6e-7884-b606-5af761b51ae8
019b3803-8b6e-799e-8a2a-12dea070dd06
019b3803-8b6e-7ab9-a22d-864de02ad603
019b3803-8b6e-7bcf-a6da-783ea33c8227
019b3803-8b6e-7cea-ba0b-0b122d542738
019b3803-8b6e-7e05-b981-8b222d8db269
019b3803-8b6e-7f1b-a23d-5917ff408bc0

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)

1f0dd0e1-df7e-6162-9868-4cf95d479851
1f0dd0e1-df7e-62fc-9868-4cf95d479851
1f0dd0e1-df7e-63e2-9868-4cf95d479851
1f0dd0e1-df7e-64aa-9868-4cf95d479851
1f0dd0e1-df7e-6572-9868-4cf95d479851
1f0dd0e1-df7e-663a-9868-4cf95d479851
1f0dd0e1-df7e-66f8-9868-4cf95d479851
1f0dd0e1-df7e-67c0-9868-4cf95d479851
1f0dd0e1-df7e-6888-9868-4cf95d479851
1f0dd0e1-df7e-6950-9868-4cf95d479851
1f0dd0e1-df7e-6ab8-9868-4cf95d479851
1f0dd0e1-df7e-6b8a-9868-4cf95d479851
1f0dd0e1-df7e-6c52-9868-4cf95d479851
1f0dd0e1-df7e-6d10-9868-4cf95d479851
1f0dd0e1-df7e-6dce-9868-4cf95d479851

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)

5fe0056a-2ed3-4fcb-ac55-163c08e0262e
36521edd-10b2-405c-aeae-0faee17e47bd
62e231f8-2295-45b2-8a66-f9d4ba0e531e
4e6b1e60-7e13-43d9-99e1-1afe0e3cb54b
2ae1435d-c35b-486a-80e7-6b8bfccbc094
42ca1d94-68df-4388-8ae3-bafdcaad1407
bc47d6d9-d83d-4b2b-9866-34f6a267271e
7e3e1057-a472-4943-b7e9-ebac2ffc2df2
ddd98f73-56d7-46a6-8709-810c5286054b
5d208885-b872-4c17-92f6-35bdc54c59d7
90a3e335-79f1-4b03-85c9-a08f9ed5c084
693b77aa-14b2-4479-a779-0a07b614e670
658b8dfc-85cd-454d-a144-62e4bdeba2b1
eea4e56c-6aa7-455b-915f-4db62da91bd8
e49f37d6-3c6e-4b1b-8c67-468a275a6b88

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)

1df7f2ec-dd0e-11f0-9868-4cf95d479851
1df7f350-dd0e-11f0-9868-4cf95d479851
1df7f3be-dd0e-11f0-9868-4cf95d479851
1df7f42c-dd0e-11f0-9868-4cf95d479851
1df7f490-dd0e-11f0-9868-4cf95d479851
1df7f4fe-dd0e-11f0-9868-4cf95d479851
1df7f562-dd0e-11f0-9868-4cf95d479851
1df7f5bc-dd0e-11f0-9868-4cf95d479851
1df7f620-dd0e-11f0-9868-4cf95d479851
1df7f684-dd0e-11f0-9868-4cf95d479851
1df7f6e8-dd0e-11f0-9868-4cf95d479851
1df7f74c-dd0e-11f0-9868-4cf95d479851
1df7f7a6-dd0e-11f0-9868-4cf95d479851
1df7f800-dd0e-11f0-9868-4cf95d479851
1df7f864-dd0e-11f0-9868-4cf95d479851

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)

f26b0e23-7d04-8116-87e9-5ce32bd83b97
46660f23-7d04-8116-87e9-5ce32bd83b97
483c1023-7d04-8116-87e9-5ce32bd83b97
46371123-7d04-8116-87e9-5ce32bd83b97
8a931223-7d04-8116-87e9-5ce32bd83b97
c5551323-7d04-8116-87e9-5ce32bd83b97
79231423-7d04-8116-87e9-5ce32bd83b97
fc1a1523-7d04-8116-87e9-5ce32bd83b97
3cd41623-7d04-8116-87e9-5ce32bd83b97
a5461723-7d04-8116-87e9-5ce32bd83b97
47561923-7d04-8116-87e9-5ce32bd83b97
6b801a23-7d04-8116-87e9-5ce32bd83b97
48331b23-7d04-8116-87e9-5ce32bd83b97
a7251c23-7d04-8116-87e9-5ce32bd83b97
e1881d23-7d04-8116-87e9-5ce32bd83b97

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: