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)

019ebbe9-9172-7b61-98ce-3bd2f41839fa
019ebbe9-9172-7ce6-a743-1aa56fad8cb7
019ebbe9-9172-7e1d-b2f1-b352d1883f0b
019ebbe9-9172-7f3c-b390-7f9b159acba1
019ebbe9-9173-7052-889e-59990516d386
019ebbe9-9173-7169-ab1e-b7679d389f44
019ebbe9-9173-727b-9b65-86064218cd87
019ebbe9-9173-738e-bb36-307759b1898a
019ebbe9-9173-74a4-9a74-d00bec99aaed
019ebbe9-9173-75b7-84e6-bd743e4a4f9a
019ebbe9-9173-76cd-96b7-8ee7b811dfc8
019ebbe9-9173-77e0-b51a-83df32893f06
019ebbe9-9173-78f2-9525-c7b341efa319
019ebbe9-9173-7a09-8cf4-58342101cda9
019ebbe9-9173-7b1b-b2ab-73c9050e46b4

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)

1f1665e6-742f-6b16-aa7d-4cf95d479851
1f1665e6-742f-6ca6-aa7d-4cf95d479851
1f1665e6-742f-6d8c-aa7d-4cf95d479851
1f1665e6-742f-6e54-aa7d-4cf95d479851
1f1665e6-742f-6f1c-aa7d-4cf95d479851
1f1665e6-742f-6fda-aa7d-4cf95d479851
1f1665e6-7430-6098-aa7d-4cf95d479851
1f1665e6-7430-6156-aa7d-4cf95d479851
1f1665e6-7430-6214-aa7d-4cf95d479851
1f1665e6-7430-62d2-aa7d-4cf95d479851
1f1665e6-7430-6412-aa7d-4cf95d479851
1f1665e6-7430-64e4-aa7d-4cf95d479851
1f1665e6-7430-65a2-aa7d-4cf95d479851
1f1665e6-7430-6660-aa7d-4cf95d479851
1f1665e6-7430-6714-aa7d-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)

674307e6-665e-11f1-aa7d-4cf95d479851
6743084a-665e-11f1-aa7d-4cf95d479851
674308a4-665e-11f1-aa7d-4cf95d479851
674308fe-665e-11f1-aa7d-4cf95d479851
67430962-665e-11f1-aa7d-4cf95d479851
674309bc-665e-11f1-aa7d-4cf95d479851
67430a16-665e-11f1-aa7d-4cf95d479851
67430a7a-665e-11f1-aa7d-4cf95d479851
67430ad4-665e-11f1-aa7d-4cf95d479851
67430b2e-665e-11f1-aa7d-4cf95d479851
67430b88-665e-11f1-aa7d-4cf95d479851
67430be2-665e-11f1-aa7d-4cf95d479851
67430c50-665e-11f1-aa7d-4cf95d479851
67430cb4-665e-11f1-aa7d-4cf95d479851
67430d18-665e-11f1-aa7d-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)

63890f1b-0b03-830a-87ea-5ce32bd83b97
9785101b-0b03-830a-87ea-5ce32bd83b97
89d5111b-0b03-830a-87ea-5ce32bd83b97
9165121b-0b03-830a-87ea-5ce32bd83b97
9837131b-0b03-830a-87ea-5ce32bd83b97
9313141b-0b03-830a-87ea-5ce32bd83b97
9965151b-0b03-830a-87ea-5ce32bd83b97
2975161b-0b03-830a-87ea-5ce32bd83b97
25c1171b-0b03-830a-87ea-5ce32bd83b97
0df7191b-0b03-830a-87ea-5ce32bd83b97
5e0d1a1b-0b03-830a-87ea-5ce32bd83b97
982c1b1b-0b03-830a-87ea-5ce32bd83b97
b0cc1c1b-0b03-830a-87ea-5ce32bd83b97
15421d1b-0b03-830a-87ea-5ce32bd83b97
585a1e1b-0b03-830a-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)

acb66263-07dc-4f79-aff4-79523878a8cc
4d9e4ecb-6c45-4f7d-bcda-939af57913dd
52a3104c-d7ec-414c-bea5-1af38995ed1a
7a69020c-b27e-4c30-9efd-960acacd2a9f
734fd837-1987-487b-87c8-d87772518a31
0cec8edd-b0a2-43e0-ae36-599df0c6d9fa
1a569db4-4f9a-4c10-bdac-1b4f027200e4
f84d81ae-4bd4-4ecf-85a3-064eb8a7389d
0e7feebe-96e9-428a-9fb0-a45c7ce025cc
f602cc40-5ab9-4684-8013-010cf568c410
c1ef2633-ea8d-465d-a4be-7fba2c9b42f2
b2fd42d9-8a5c-474f-b019-0db6340266d9
644213e8-bb8e-4684-8adb-6fe2d7e35486
cc4c4528-2ac8-471f-b71f-aa64ebe0b4a1
cb213553-e3d8-4931-9490-c96bc360bf69

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: