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)

01966063-82a9-76cd-a5a1-07e893a3e312
01966063-82a9-789c-9f39-6365d9b27955
01966063-82a9-79e4-a00f-2290b98377fa
01966063-82a9-7b07-957c-c0df7ad143e5
01966063-82a9-7c25-aeb3-0a9b18e7771c
01966063-82a9-7d40-9602-355aa059421f
01966063-82a9-7e5b-b8f4-e128f82cb8fd
01966063-82a9-7f75-8884-bb68c7e93c18
01966063-82aa-7090-a467-f4c4e61e71e4
01966063-82aa-71af-8083-99c33e5ec3cc
01966063-82aa-72c9-bfbc-bd9f4f309dc9
01966063-82aa-73e4-9270-f092a07b74ff
01966063-82aa-74fe-baaa-00bd2b21e7aa
01966063-82aa-7615-bac4-2ee284e0bb85
01966063-82aa-7730-83db-d49b33ec8e1d

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)

1f01fe74-2a16-6784-b704-4cf95d479851
1f01fe74-2a16-693c-b704-4cf95d479851
1f01fe74-2a16-6a2c-b704-4cf95d479851
1f01fe74-2a16-6afe-b704-4cf95d479851
1f01fe74-2a16-6bd0-b704-4cf95d479851
1f01fe74-2a16-6c98-b704-4cf95d479851
1f01fe74-2a16-6d6a-b704-4cf95d479851
1f01fe74-2a16-6e32-b704-4cf95d479851
1f01fe74-2a16-6efa-b704-4cf95d479851
1f01fe74-2a16-6fc2-b704-4cf95d479851
1f01fe74-2a17-613e-b704-4cf95d479851
1f01fe74-2a17-62ce-b704-4cf95d479851
1f01fe74-2a17-6418-b704-4cf95d479851
1f01fe74-2a17-64ea-b704-4cf95d479851
1f01fe74-2a17-65a8-b704-4cf95d479851

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)

25c6324a-018c-493d-a7ca-0db02e75ee72
ab975976-1d33-4ea4-9a4a-c4aa78a0be83
33f3aacf-9a83-4032-8fa8-819c068f0fec
1abb431c-ee3c-4470-b517-5af87dec39ee
14ac33b7-6226-4fd0-87a1-92c9b4b30f02
68597b6e-18db-4f45-811a-d2ce12595779
b8a52d2d-3ec9-444f-8feb-d2607ca44255
c04bf7da-66ea-4b28-971a-a353acec6567
af69384c-658d-4b51-99da-88dde814f0ab
42a5b300-0988-4744-ace5-8ccbebb47121
77305562-b936-4537-bd97-17c33c5cf479
3d232a1e-dc0d-4d86-b801-bf4f4945a73c
5a956229-28a1-4935-821f-210190513bb8
d63fb61f-de1b-4f44-8d88-f41efe3ee91e
7ead0a18-12b5-4ae8-aa92-41ae2f811416

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)

42a17ac6-1fe7-11f0-b704-4cf95d479851
42a17b34-1fe7-11f0-b704-4cf95d479851
42a17b98-1fe7-11f0-b704-4cf95d479851
42a17bfc-1fe7-11f0-b704-4cf95d479851
42a17c6a-1fe7-11f0-b704-4cf95d479851
42a17cce-1fe7-11f0-b704-4cf95d479851
42a17d3c-1fe7-11f0-b704-4cf95d479851
42a17daa-1fe7-11f0-b704-4cf95d479851
42a17e0e-1fe7-11f0-b704-4cf95d479851
42a17e7c-1fe7-11f0-b704-4cf95d479851
42a17ee0-1fe7-11f0-b704-4cf95d479851
42a17f44-1fe7-11f0-b704-4cf95d479851
42a17fa8-1fe7-11f0-b704-4cf95d479851
42a18016-1fe7-11f0-b704-4cf95d479851
42a18084-1fe7-11f0-b704-4cf95d479851

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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

3aeb6d10-007d-8071-87e9-5ce32bd83b96
28eb6e10-007d-8071-87e9-5ce32bd83b96
e5cb6f10-007d-8071-87e9-5ce32bd83b96
1ae47010-007d-8071-87e9-5ce32bd83b96
b1d67110-007d-8071-87e9-5ce32bd83b96
cd577210-007d-8071-87e9-5ce32bd83b96
ad527310-007d-8071-87e9-5ce32bd83b96
79c37410-007d-8071-87e9-5ce32bd83b96
22867510-007d-8071-87e9-5ce32bd83b96
a8a67610-007d-8071-87e9-5ce32bd83b96
3ff77710-007d-8071-87e9-5ce32bd83b96
60017810-007d-8071-87e9-5ce32bd83b96
091f7a10-007d-8071-87e9-5ce32bd83b96
24387b10-007d-8071-87e9-5ce32bd83b96
32497c10-007d-8071-87e9-5ce32bd83b96

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: