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)

01a1296c-e578-7ec1-beeb-785cc3218e53
01a1296c-e579-705b-a3be-63f246f41d40
01a1296c-e579-719a-bc49-f45b67c72ac1
01a1296c-e579-72b9-8a37-e3b072b3728d
01a1296c-e579-73e4-9157-a01b4bca5866
01a1296c-e579-74fa-a5f3-55cc3e7772ed
01a1296c-e579-7611-ab88-9df52c4bbc11
01a1296c-e579-7727-9742-994c5d9cda18
01a1296c-e579-783a-9b81-d5ccec06053d
01a1296c-e579-795d-9fe7-49df13a894a0
01a1296c-e579-7a73-81b2-9083025065c4
01a1296c-e579-7b8a-bca0-bea627ec4c31
01a1296c-e579-7ca0-9721-697430dc87ce
01a1296c-e579-7db3-9117-e22f5e71eba7
01a1296c-e579-7ec9-9927-0a8f1a16ad45

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)

1f1c5344-1453-6052-8e1b-4cf95d479851
1f1c5344-1453-6228-8e1b-4cf95d479851
1f1c5344-1453-6304-8e1b-4cf95d479851
1f1c5344-1453-63d6-8e1b-4cf95d479851
1f1c5344-1453-649e-8e1b-4cf95d479851
1f1c5344-1453-655c-8e1b-4cf95d479851
1f1c5344-1453-6624-8e1b-4cf95d479851
1f1c5344-1453-66ec-8e1b-4cf95d479851
1f1c5344-1453-67aa-8e1b-4cf95d479851
1f1c5344-1453-6868-8e1b-4cf95d479851
1f1c5344-1453-69b2-8e1b-4cf95d479851
1f1c5344-1453-6a7a-8e1b-4cf95d479851
1f1c5344-1453-6b42-8e1b-4cf95d479851
1f1c5344-1453-6c00-8e1b-4cf95d479851
1f1c5344-1453-6cbe-8e1b-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)

41453d90-c534-11f1-8e1b-4cf95d479851
41453dfe-c534-11f1-8e1b-4cf95d479851
41453e62-c534-11f1-8e1b-4cf95d479851
41453ec6-c534-11f1-8e1b-4cf95d479851
41453f34-c534-11f1-8e1b-4cf95d479851
41453f8e-c534-11f1-8e1b-4cf95d479851
41453ff2-c534-11f1-8e1b-4cf95d479851
41454060-c534-11f1-8e1b-4cf95d479851
414540c4-c534-11f1-8e1b-4cf95d479851
41454128-c534-11f1-8e1b-4cf95d479851
4145418c-c534-11f1-8e1b-4cf95d479851
414541e6-c534-11f1-8e1b-4cf95d479851
4145424a-c534-11f1-8e1b-4cf95d479851
414542ae-c534-11f1-8e1b-4cf95d479851
41454312-c534-11f1-8e1b-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)

8878eb04-4701-8c11-87ea-5ce32bd83b97
2236ec04-4701-8c11-87ea-5ce32bd83b97
4269ee04-4701-8c11-87ea-5ce32bd83b97
cc9def04-4701-8c11-87ea-5ce32bd83b97
f148f004-4701-8c11-87ea-5ce32bd83b97
3cd5f104-4701-8c11-87ea-5ce32bd83b97
b943f204-4701-8c11-87ea-5ce32bd83b97
5833f304-4701-8c11-87ea-5ce32bd83b97
c9bdf404-4701-8c11-87ea-5ce32bd83b97
2ad6f504-4701-8c11-87ea-5ce32bd83b97
dd26f604-4701-8c11-87ea-5ce32bd83b97
285ff704-4701-8c11-87ea-5ce32bd83b97
ba67f804-4701-8c11-87ea-5ce32bd83b97
9822f904-4701-8c11-87ea-5ce32bd83b97
a8f3fa04-4701-8c11-87ea-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)

c9bc76ad-cc3b-4a6a-ac2b-f3330fedd428
1236e9f6-5a08-41c3-a4a2-0152faac4f3c
c51489d0-c890-4c36-a1bb-e5cd251d264d
87d5efbd-1146-4f61-8b11-c493b3a74ce9
aaf912ed-ae63-43f6-a3a3-f3a58e397280
67787d8d-5b5c-425c-be51-35f5f8f95091
6091e3a4-728b-4eb9-b7fa-49d1f2b2b3fb
f8041126-603a-4e2a-ad0a-14086ef0bab9
b2a72625-555e-43bc-958c-6e6fdb10dbc6
6a27936c-ded4-4b68-9285-23f168a28e64
ee9be93a-f90a-4a68-a74f-617f5cb189dd
45a2816c-a30d-4353-9cee-f3c08077bf65
50cc3c3c-e875-49d6-a6c8-75ca8fddea49
51c7c84d-bce4-4808-8471-ed82d2346c66
7753c3e2-6334-421c-b79a-baf4b7a667da

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: