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)

01a0648d-dfe9-7113-8276-d57b565197e3
01a0648d-dfe9-72de-b239-02198d15ef78
01a0648d-dfe9-7409-b791-be6274759a67
01a0648d-dfe9-7527-a80e-ece0247bf37c
01a0648d-dfe9-763e-9ad5-4ff32910deac
01a0648d-dfe9-7754-82af-f3a0db82fb91
01a0648d-dfe9-786b-b699-4630cf092699
01a0648d-dfe9-7986-a940-4e7255f48bad
01a0648d-dfe9-7a98-a5a4-35e0235fc9a6
01a0648d-dfe9-7bb7-807f-3ee8644a33b8
01a0648d-dfe9-7ccd-a994-ab2462bf663b
01a0648d-dfe9-7de4-af6a-8061cb86d161
01a0648d-dfe9-7efa-af39-29a2c7ebf6ac
01a0648d-dfea-7011-9866-19eefda8d963
01a0648d-dfea-7127-9941-9c325ffe502c

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)

1f1a729f-97be-6e82-8bab-4cf95d479851
1f1a729f-97bf-6062-8bab-4cf95d479851
1f1a729f-97bf-6152-8bab-4cf95d479851
1f1a729f-97bf-6224-8bab-4cf95d479851
1f1a729f-97bf-62ec-8bab-4cf95d479851
1f1a729f-97bf-63b4-8bab-4cf95d479851
1f1a729f-97bf-647c-8bab-4cf95d479851
1f1a729f-97bf-6544-8bab-4cf95d479851
1f1a729f-97bf-660c-8bab-4cf95d479851
1f1a729f-97bf-66d4-8bab-4cf95d479851
1f1a729f-97bf-6828-8bab-4cf95d479851
1f1a729f-97bf-68fa-8bab-4cf95d479851
1f1a729f-97bf-69b8-8bab-4cf95d479851
1f1a729f-97bf-6a80-8bab-4cf95d479851
1f1a729f-97bf-6b3e-8bab-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)

f97bfc1a-a729-11f1-8bab-4cf95d479851
f97bfc7e-a729-11f1-8bab-4cf95d479851
f97bfce2-a729-11f1-8bab-4cf95d479851
f97bfd46-a729-11f1-8bab-4cf95d479851
f97bfdaa-a729-11f1-8bab-4cf95d479851
f97bfe0e-a729-11f1-8bab-4cf95d479851
f97bfe72-a729-11f1-8bab-4cf95d479851
f97bfee0-a729-11f1-8bab-4cf95d479851
f97bff44-a729-11f1-8bab-4cf95d479851
f97bffa8-a729-11f1-8bab-4cf95d479851
f97c0016-a729-11f1-8bab-4cf95d479851
f97c007a-a729-11f1-8bab-4cf95d479851
f97c00de-a729-11f1-8bab-4cf95d479851
f97c014c-a729-11f1-8bab-4cf95d479851
f97c01b0-a729-11f1-8bab-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)

e774a236-9d05-850f-87ea-5ce32bd83b97
35e4a336-9d05-850f-87ea-5ce32bd83b97
9d38a436-9d05-850f-87ea-5ce32bd83b97
e51ea536-9d05-850f-87ea-5ce32bd83b97
748ba636-9d05-850f-87ea-5ce32bd83b97
79a5a736-9d05-850f-87ea-5ce32bd83b97
17c7a836-9d05-850f-87ea-5ce32bd83b97
e175a936-9d05-850f-87ea-5ce32bd83b97
8e70aa36-9d05-850f-87ea-5ce32bd83b97
3ab1ab36-9d05-850f-87ea-5ce32bd83b97
0505ac36-9d05-850f-87ea-5ce32bd83b97
ac40ad36-9d05-850f-87ea-5ce32bd83b97
4ae6ae36-9d05-850f-87ea-5ce32bd83b97
8b31af36-9d05-850f-87ea-5ce32bd83b97
8976b036-9d05-850f-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)

0ee5279b-2be1-435a-9375-1f6a1c315ec4
4b8cd8ab-df8f-4506-8117-9d2bca6bd2c0
14918480-c228-4dfc-b2be-a449b430e3ab
9615d287-b7d3-4ce2-bacd-0fe0b5030b57
7235b7ec-8a49-4e3d-94f1-9b93662b9cac
73744a04-ba00-48a8-b839-594c44796b8f
63232873-5b17-4195-9498-5d178e542cc3
e99b6015-48e0-4900-bccd-33f2664e0c5c
28aea93b-6e80-4f68-8e36-fcae5d20c1e7
15b90090-aa24-4ce7-81f9-e93e17b6a060
d4ab0107-96f7-46c6-a31e-b0a996fd1e08
ca225d5e-b8b7-4223-bb55-88a03370dc86
f4acedaf-8a70-40c0-b616-7bf5959bbe42
d98ac698-7bc7-4247-bf1d-9d0bea56975c
c5f60672-a558-4185-9669-ec83126a75b3

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: