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)

019a7d8a-b260-7a29-a792-4de864463ba7
019a7d8a-b260-7be0-a19e-8b8178f8f449
019a7d8a-b260-7d27-8c59-6edcaa2d14c9
019a7d8a-b260-7e4a-ae76-f39911002e84
019a7d8a-b260-7f69-8cd5-f81688686820
019a7d8a-b261-7088-aa65-a12bfdad196a
019a7d8a-b261-71a2-83f1-109edc0670ef
019a7d8a-b261-72bd-91de-8581d357135d
019a7d8a-b261-73dc-a6cf-70dc873c1f08
019a7d8a-b261-74f6-bea4-fe87ebb32e79
019a7d8a-b261-7615-a5bb-631035ba3112
019a7d8a-b261-7730-a69c-d82335470c38
019a7d8a-b261-784a-a8a0-ccfaeddcd4bd
019a7d8a-b261-796d-84b6-c7c0e1fa4965
019a7d8a-b261-7a88-bff3-f2eacac63373

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)

1f0c09a0-d594-6ad4-a25a-4cf95d479851
1f0c09a0-d594-6c78-a25a-4cf95d479851
1f0c09a0-d594-6d68-a25a-4cf95d479851
1f0c09a0-d594-6e3a-a25a-4cf95d479851
1f0c09a0-d594-6f02-a25a-4cf95d479851
1f0c09a0-d594-6fca-a25a-4cf95d479851
1f0c09a0-d595-6092-a25a-4cf95d479851
1f0c09a0-d595-615a-a25a-4cf95d479851
1f0c09a0-d595-6218-a25a-4cf95d479851
1f0c09a0-d595-62e0-a25a-4cf95d479851
1f0c09a0-d595-6434-a25a-4cf95d479851
1f0c09a0-d595-64fc-a25a-4cf95d479851
1f0c09a0-d595-65c4-a25a-4cf95d479851
1f0c09a0-d595-6682-a25a-4cf95d479851
1f0c09a0-d595-674a-a25a-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)

9f21e62b-b903-4d4a-89bf-d92cc68cf2c0
17210fc3-89fc-4b86-a2dd-16945a0ff1f6
15c8adaa-7713-4027-9697-4d1c136dcb08
11192c75-d3fe-45cb-b035-b0d89b05787e
0f413e5d-8cac-4883-a0a8-fd83c41a0f5a
f65dc944-70a5-41cb-ba76-125e2da395dc
2cefcd44-0f21-485f-b87c-68d37d7de12b
b60c04ae-9b4b-48c6-a1b8-248d46fbf959
09e7b7f9-e031-4886-acbc-4a4abb565846
8f63173a-4b4e-4c43-8886-47153800acc0
6ce1a757-8eb9-4c3e-9c04-af2b7497736b
6bd08028-a364-4e46-9fdd-82ae8c49b6ef
37405c9c-7a70-4574-83e9-e66e1178e815
e6d2d7a9-0777-47a0-a6cc-02084787faf3
98a6384e-bbd9-4d03-bae7-d1703581c836

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)

0d595c72-c09a-11f0-a25a-4cf95d479851
0d595cd6-c09a-11f0-a25a-4cf95d479851
0d595d3a-c09a-11f0-a25a-4cf95d479851
0d595d94-c09a-11f0-a25a-4cf95d479851
0d595df8-c09a-11f0-a25a-4cf95d479851
0d595e52-c09a-11f0-a25a-4cf95d479851
0d595eb6-c09a-11f0-a25a-4cf95d479851
0d595f1a-c09a-11f0-a25a-4cf95d479851
0d595f74-c09a-11f0-a25a-4cf95d479851
0d595fce-c09a-11f0-a25a-4cf95d479851
0d596032-c09a-11f0-a25a-4cf95d479851
0d59608c-c09a-11f0-a25a-4cf95d479851
0d5960f0-c09a-11f0-a25a-4cf95d479851
0d59614a-c09a-11f0-a25a-4cf95d479851
0d5961a4-c09a-11f0-a25a-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)

36a2fe0c-5003-8d13-87e9-5ce32bd83b97
c5b9ff0c-5003-8d13-87e9-5ce32bd83b97
72a8010d-5003-8d13-87e9-5ce32bd83b97
6e89020d-5003-8d13-87e9-5ce32bd83b97
9c7b030d-5003-8d13-87e9-5ce32bd83b97
3c6a040d-5003-8d13-87e9-5ce32bd83b97
8687050d-5003-8d13-87e9-5ce32bd83b97
6230060d-5003-8d13-87e9-5ce32bd83b97
7555070d-5003-8d13-87e9-5ce32bd83b97
5dc9080d-5003-8d13-87e9-5ce32bd83b97
2dbb090d-5003-8d13-87e9-5ce32bd83b97
42900a0d-5003-8d13-87e9-5ce32bd83b97
b6dd0b0d-5003-8d13-87e9-5ce32bd83b97
c55b0c0d-5003-8d13-87e9-5ce32bd83b97
ce210d0d-5003-8d13-87e9-5ce32bd83b97

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: