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)

019df6fd-f612-7744-bf43-f1d1272d92fd
019df6fd-f612-78cd-b024-b18757f427d2
019df6fd-f612-7a0d-aff4-47859b6b428d
019df6fd-f612-7b27-9511-f96576a22593
019df6fd-f612-7c3a-978e-ad0c1956efa4
019df6fd-f612-7d4c-8b81-e6640d7095d6
019df6fd-f612-7e6b-85fc-a2afa6fc7de0
019df6fd-f612-7f8e-9878-93dd6f98e8f4
019df6fd-f613-70a4-bc56-1b71b2098c9d
019df6fd-f613-71bb-9d75-c00d8ac88e1f
019df6fd-f613-72d1-a311-cecb71467eb0
019df6fd-f613-73e4-88a2-9ff0905d2186
019df6fd-f613-74f6-8855-54584aab7492
019df6fd-f613-7609-a674-0ffe21370ff5
019df6fd-f613-771b-945f-dd14a4d9917a

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)

1f148523-3dd9-6b70-8c01-4cf95d479851
1f148523-3dd9-6d14-8c01-4cf95d479851
1f148523-3dd9-6e04-8c01-4cf95d479851
1f148523-3dd9-6ed6-8c01-4cf95d479851
1f148523-3dd9-6f9e-8c01-4cf95d479851
1f148523-3dda-6066-8c01-4cf95d479851
1f148523-3dda-6138-8c01-4cf95d479851
1f148523-3dda-6200-8c01-4cf95d479851
1f148523-3dda-62c8-8c01-4cf95d479851
1f148523-3dda-6390-8c01-4cf95d479851
1f148523-3dda-64da-8c01-4cf95d479851
1f148523-3dda-65b6-8c01-4cf95d479851
1f148523-3dda-667e-8c01-4cf95d479851
1f148523-3dda-6746-8c01-4cf95d479851
1f148523-3dda-691c-8c01-4cf95d479851

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)

140d9e20-9d1b-4bcd-957c-1c18a58f702c
a787ad1e-090b-4101-bdc6-e8d23db6d0f7
5f552a31-3b2c-43f9-a76f-c992ed6b715b
5a7e8e08-ca50-4f18-b5dc-af21b5d3c8cf
8c6c549c-8f34-472a-8faa-6399aee89e70
20f2967e-82e0-4e03-b59a-443825fe484f
4caad680-55df-44f0-8f1e-65a0c1e1f9ee
ceef239b-73c1-48ca-bc3d-7d82214ec60b
35940671-0df6-4b57-8924-ff3edc44ad5b
b24223c0-4e68-4024-b8d8-7dc52b424762
1ad63b11-0c42-40e8-81c8-6d200d6809ba
405f2897-a378-4c3e-8fe3-5b4bdcd6091d
36369ab9-a177-425f-9333-bca9c5e1c283
e8f0307e-4969-4995-a9ff-75bc6c54a891
be2ad14f-d222-48f9-a56b-32e8360408b2

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)

33ddaf34-4852-11f1-8c01-4cf95d479851
33ddafa2-4852-11f1-8c01-4cf95d479851
33ddb010-4852-11f1-8c01-4cf95d479851
33ddb07e-4852-11f1-8c01-4cf95d479851
33ddb0e2-4852-11f1-8c01-4cf95d479851
33ddb146-4852-11f1-8c01-4cf95d479851
33ddb1b4-4852-11f1-8c01-4cf95d479851
33ddb20e-4852-11f1-8c01-4cf95d479851
33ddb27c-4852-11f1-8c01-4cf95d479851
33ddb2e0-4852-11f1-8c01-4cf95d479851
33ddb344-4852-11f1-8c01-4cf95d479851
33ddb3b2-4852-11f1-8c01-4cf95d479851
33ddb416-4852-11f1-8c01-4cf95d479851
33ddb48e-4852-11f1-8c01-4cf95d479851
33ddb4fc-4852-11f1-8c01-4cf95d479851

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)

98b2fc1f-b401-8d07-87ea-5ce32bd83b97
1f2ffd1f-b401-8d07-87ea-5ce32bd83b97
3a3efe1f-b401-8d07-87ea-5ce32bd83b97
b90e0020-b401-8d07-87ea-5ce32bd83b97
cc560120-b401-8d07-87ea-5ce32bd83b97
c1dd0220-b401-8d07-87ea-5ce32bd83b97
eba20320-b401-8d07-87ea-5ce32bd83b97
31390420-b401-8d07-87ea-5ce32bd83b97
9ef20520-b401-8d07-87ea-5ce32bd83b97
503f0620-b401-8d07-87ea-5ce32bd83b97
e9f50720-b401-8d07-87ea-5ce32bd83b97
dbd50820-b401-8d07-87ea-5ce32bd83b97
a4b60920-b401-8d07-87ea-5ce32bd83b97
e0b20a20-b401-8d07-87ea-5ce32bd83b97
72d00b20-b401-8d07-87ea-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: