UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

01a0dba9-3594-7e6f-9523-166f46911030
01a0dba9-3594-7000-87e2-fe7abdd1ea75
01a0dba9-3595-713c-be3b-1dbdcedd106b
01a0dba9-3595-7257-a3c9-1a0e0bbe554b
01a0dba9-3595-736d-8cf0-70b85ea50da2
01a0dba9-3595-73fc-879c-ba53145caab2
01a0dba9-3595-7517-895d-a6b8880146f6
01a0dba9-3595-762e-87a9-eb8e950f46cb
01a0dba9-3595-7744-bd9d-7bdedf5888fa
01a0dba9-3595-785b-99ef-0a73b3e1a0b5
01a0dba9-3595-7975-99f2-ac399d563f99
01a0dba9-3595-7a88-9808-60cf769daefe
01a0dba9-3595-7b9e-b6bd-d2f291dd7b1f
01a0dba9-3595-7cb5-97dd-ac097a8ef301
01a0dba9-3595-7dc7-9668-37a4a9a06342

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)

1f1b9569-53e7-61b2-b123-4cf95d479851
1f1b9569-53e7-6374-b123-4cf95d479851
1f1b9569-53e7-645a-b123-4cf95d479851
1f1b9569-53e7-6522-b123-4cf95d479851
1f1b9569-53e7-65ea-b123-4cf95d479851
1f1b9569-53e7-66b2-b123-4cf95d479851
1f1b9569-53e7-6770-b123-4cf95d479851
1f1b9569-53e7-682e-b123-4cf95d479851
1f1b9569-53e7-68ec-b123-4cf95d479851
1f1b9569-53e7-69aa-b123-4cf95d479851
1f1b9569-53e7-6b30-b123-4cf95d479851
1f1b9569-53e7-6c98-b123-4cf95d479851
1f1b9569-53e7-6d88-b123-4cf95d479851
1f1b9569-53e7-6e46-b123-4cf95d479851
1f1b9569-53e7-6f0e-b123-4cf95d479851

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)

953e7ff4-b956-11f1-b123-4cf95d479851
953e8058-b956-11f1-b123-4cf95d479851
953e80bc-b956-11f1-b123-4cf95d479851
953e8120-b956-11f1-b123-4cf95d479851
953e8184-b956-11f1-b123-4cf95d479851
953e81e8-b956-11f1-b123-4cf95d479851
953e8242-b956-11f1-b123-4cf95d479851
953e82b0-b956-11f1-b123-4cf95d479851
953e831e-b956-11f1-b123-4cf95d479851
953e838c-b956-11f1-b123-4cf95d479851
953e83f0-b956-11f1-b123-4cf95d479851
953e8454-b956-11f1-b123-4cf95d479851
953e84ae-b956-11f1-b123-4cf95d479851
953e8512-b956-11f1-b123-4cf95d479851
953e8576-b956-11f1-b123-4cf95d479851

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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

40c5bd22-b600-8d10-87ea-5ce32bd83b97
6218be22-b600-8d10-87ea-5ce32bd83b97
c266bf22-b600-8d10-87ea-5ce32bd83b97
6280c022-b600-8d10-87ea-5ce32bd83b97
eb80c122-b600-8d10-87ea-5ce32bd83b97
1fbdc322-b600-8d10-87ea-5ce32bd83b97
2ee3c422-b600-8d10-87ea-5ce32bd83b97
9655c522-b600-8d10-87ea-5ce32bd83b97
7219c622-b600-8d10-87ea-5ce32bd83b97
0c63c722-b600-8d10-87ea-5ce32bd83b97
6d6dc822-b600-8d10-87ea-5ce32bd83b97
d0afc922-b600-8d10-87ea-5ce32bd83b97
aba0ca22-b600-8d10-87ea-5ce32bd83b97
2d82cb22-b600-8d10-87ea-5ce32bd83b97
78e6cc22-b600-8d10-87ea-5ce32bd83b97

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)

19c4d4a6-a340-463c-82e7-c0d51ab80345
239d4483-31ef-4834-8a30-8d102410cd24
b7ab9dc6-e0fd-4ff4-bac5-ffad30f7cd3f
f293140d-1724-4e17-9e61-c6c5f660a5e0
49862223-59cd-42a6-ad50-93956f5e5f26
3a5e27fb-1871-4d94-99d9-72335e816f30
3638b6f9-2002-47b3-8908-bc097d6fb1b5
7709a16c-7d6f-4cd5-9272-0dd9d06ee216
60431fca-c8e8-43a8-8480-857a56b2470f
7bd8e7fe-1620-4122-9835-48a0ec013181
efcd59e8-cd6b-4f70-b822-3f47f1bbfb3f
e18e2935-156a-4d7c-a1e5-fd9f9f0d68c7
5df56ffa-8062-41a8-9496-3a1b7ce4873e
2deac0af-e622-4604-968e-5f956033a0e9
6aedd5b3-7678-4669-b861-dde62c227682

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: