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)

019cd3c4-11f7-7ca4-baf4-aaf96c79e2fe
019cd3c4-11f7-7e2e-92bd-c8d88337e2db
019cd3c4-11f7-7f6d-9a9c-42a574b9cc17
019cd3c4-11f8-7090-a8b6-c089106c6a25
019cd3c4-11f8-71aa-b053-29f488e470f0
019cd3c4-11f8-72c1-b03d-49fe38b4e7b0
019cd3c4-11f8-73dc-95cc-9c4b7d49c935
019cd3c4-11f8-74f6-ac03-fb021abaca28
019cd3c4-11f8-7611-8efe-6e443701c653
019cd3c4-11f8-7727-b2c7-b7cc536b8602
019cd3c4-11f8-7842-b78a-e33f3f8db96d
019cd3c4-11f8-7959-8884-3b96b5a6877d
019cd3c4-11f8-7a6f-95fe-229d196cbfed
019cd3c4-11f8-7baf-ab98-1310aedb3dfb
019cd3c4-11f8-7d03-ab4c-e3af5505fa36

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)

1f11be22-e7f4-6b5c-bae5-4cf95d479851
1f11be22-e7f4-6d00-bae5-4cf95d479851
1f11be22-e7f4-6de6-bae5-4cf95d479851
1f11be22-e7f4-6ec2-bae5-4cf95d479851
1f11be22-e7f4-6f8a-bae5-4cf95d479851
1f11be22-e7f5-6052-bae5-4cf95d479851
1f11be22-e7f5-6124-bae5-4cf95d479851
1f11be22-e7f5-61e2-bae5-4cf95d479851
1f11be22-e7f5-62aa-bae5-4cf95d479851
1f11be22-e7f5-637c-bae5-4cf95d479851
1f11be22-e7f5-64d0-bae5-4cf95d479851
1f11be22-e7f5-65a2-bae5-4cf95d479851
1f11be22-e7f5-666a-bae5-4cf95d479851
1f11be22-e7f5-673c-bae5-4cf95d479851
1f11be22-e7f5-680e-bae5-4cf95d479851

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)

04ca7501-5b6d-4c70-b4fc-6c884238831e
5294bf43-f9b2-4dac-8706-3d54b9ff911f
5058c6d2-9f32-4361-bda4-8eb0c421f23a
e8f57809-d81a-44e0-864f-e5c0848d97f9
32b4f80d-5c49-4d44-ba86-9de45b102499
45cedb0c-c081-441f-89c6-bf176bc9bbeb
68721be1-5513-45ac-8d34-b27d3259fdbd
6aff6493-c5c5-475c-9ed9-7c600bbe9703
e873a77a-c664-4e51-a995-f69dac360eca
0521ddb4-9b0b-4a86-a1cc-6541fb93dd1e
cc71e157-a03f-49ee-9baf-3ac2ceccaa12
2566e65c-bc6b-402a-a96b-c0e59b1e0c93
ace3df66-023e-472c-8964-574fcc67de42
6dee572a-ac21-43f2-ba68-cc4af8e546fc
72b05d23-0367-4472-81ad-37cdaef533c4

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)

2e7f5d40-1be2-11f1-bae5-4cf95d479851
2e7f5dae-1be2-11f1-bae5-4cf95d479851
2e7f5e12-1be2-11f1-bae5-4cf95d479851
2e7f5e6c-1be2-11f1-bae5-4cf95d479851
2e7f5ef8-1be2-11f1-bae5-4cf95d479851
2e7f5f5c-1be2-11f1-bae5-4cf95d479851
2e7f5fca-1be2-11f1-bae5-4cf95d479851
2e7f602e-1be2-11f1-bae5-4cf95d479851
2e7f6092-1be2-11f1-bae5-4cf95d479851
2e7f60ec-1be2-11f1-bae5-4cf95d479851
2e7f6150-1be2-11f1-bae5-4cf95d479851
2e7f61b4-1be2-11f1-bae5-4cf95d479851
2e7f6218-1be2-11f1-bae5-4cf95d479851
2e7f6272-1be2-11f1-bae5-4cf95d479851
2e7f62d6-1be2-11f1-bae5-4cf95d479851

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)

1fcc2f30-3b04-8404-87ea-5ce32bd83b97
1a3e3030-3b04-8404-87ea-5ce32bd83b97
b15a3130-3b04-8404-87ea-5ce32bd83b97
17823230-3b04-8404-87ea-5ce32bd83b97
2d863330-3b04-8404-87ea-5ce32bd83b97
31563430-3b04-8404-87ea-5ce32bd83b97
5f443630-3b04-8404-87ea-5ce32bd83b97
8ef63730-3b04-8404-87ea-5ce32bd83b97
94953830-3b04-8404-87ea-5ce32bd83b97
c8bf3930-3b04-8404-87ea-5ce32bd83b97
dda43a30-3b04-8404-87ea-5ce32bd83b97
99323b30-3b04-8404-87ea-5ce32bd83b97
7ee73c30-3b04-8404-87ea-5ce32bd83b97
26a63d30-3b04-8404-87ea-5ce32bd83b97
81613e30-3b04-8404-87ea-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: