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)

018f1db6-1269-7344-a510-886e4a96115e
018f1db6-1269-74cd-a8a4-c0478c53b1bf
018f1db6-1269-7611-9a96-bbdf65a0ce2f
018f1db6-1269-7738-9b65-102a34b60da6
018f1db6-1269-785b-81f5-7d103023c83b
018f1db6-1269-7979-aaa7-309c1d6f5402
018f1db6-1269-7aa0-928b-483b38aa37ee
018f1db6-1269-7bcb-b49d-8034ef409102
018f1db6-1269-7ce6-a634-d8377480699d
018f1db6-1269-7e09-8f5f-cd188178958a
018f1db6-1269-7f2c-ba89-6222bd59e098
018f1db6-126a-704a-b8ae-72dc823eb27a
018f1db6-126a-716d-9323-e5591a42a815
018f1db6-126a-728c-970b-e4d7e3f82ba0
018f1db6-126a-73aa-9206-10a2ab446785

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)

1ef044aa-bb09-69a2-833f-4cf95d479851
1ef044aa-bb09-6b46-833f-4cf95d479851
1ef044aa-bb09-6c40-833f-4cf95d479851
1ef044aa-bb09-6d1c-833f-4cf95d479851
1ef044aa-bb09-6de4-833f-4cf95d479851
1ef044aa-bb09-6f1a-833f-4cf95d479851
1ef044aa-bb0a-600a-833f-4cf95d479851
1ef044aa-bb0a-60d2-833f-4cf95d479851
1ef044aa-bb0a-61a4-833f-4cf95d479851
1ef044aa-bb0a-626c-833f-4cf95d479851
1ef044aa-bb0a-63c0-833f-4cf95d479851
1ef044aa-bb0a-64c4-833f-4cf95d479851
1ef044aa-bb0a-65e6-833f-4cf95d479851
1ef044aa-bb0a-66b8-833f-4cf95d479851
1ef044aa-bb0a-6780-833f-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)

d7e3bf31-fcfd-4be7-982e-e82bf475b87d
07b8edc0-4435-4d26-84cb-4f9c68be426a
e9070987-16e5-48ac-bbad-3729da67618b
57ef424a-a801-42b4-be4c-58c48136bf17
3945e142-6d41-4e03-a787-84938cad6b38
500e3dfc-8bc9-461f-a5de-743e97392a1b
de08cd99-abee-432d-9797-c0d1576893a3
9e3bd857-0f15-4131-8161-0c593cf8ba05
af7b4081-bc0f-4f8c-b053-d3d9a99d8464
2da1831c-5eae-401e-9983-e13844b82168
03106434-66d3-46b6-8803-a5b47c43aa35
328a399c-29be-40c2-9b50-bea51526daea
f3f9d4a8-04b4-4f8c-ab01-a8efdf404caf
fc9cbf44-dfa7-4197-9961-110632ee5ac5
f1afd249-6453-4550-9c27-32e59c034790

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)

abb0ad16-044a-11ef-833f-4cf95d479851
abb0ad84-044a-11ef-833f-4cf95d479851
abb0adf2-044a-11ef-833f-4cf95d479851
abb0ae56-044a-11ef-833f-4cf95d479851
abb0aeba-044a-11ef-833f-4cf95d479851
abb0af1e-044a-11ef-833f-4cf95d479851
abb0af8c-044a-11ef-833f-4cf95d479851
abb0afe6-044a-11ef-833f-4cf95d479851
abb0b04a-044a-11ef-833f-4cf95d479851
abb0b0ae-044a-11ef-833f-4cf95d479851
abb0b112-044a-11ef-833f-4cf95d479851
abb0b19e-044a-11ef-833f-4cf95d479851
abb0b220-044a-11ef-833f-4cf95d479851
abb0b28e-044a-11ef-833f-4cf95d479851
abb0b2f2-044a-11ef-833f-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)

4755a216-00f1-8076-87e8-5ce32bd83b96
16f0a316-00f1-8076-87e8-5ce32bd83b96
1846a416-00f1-8076-87e8-5ce32bd83b96
43dca516-00f1-8076-87e8-5ce32bd83b96
9befa616-00f1-8076-87e8-5ce32bd83b96
44a2a716-00f1-8076-87e8-5ce32bd83b96
9398a816-00f1-8076-87e8-5ce32bd83b96
e4f7a916-00f1-8076-87e8-5ce32bd83b96
ebc3aa16-00f1-8076-87e8-5ce32bd83b96
86dbab16-00f1-8076-87e8-5ce32bd83b96
fc2eac16-00f1-8076-87e8-5ce32bd83b96
434dae16-00f1-8076-87e8-5ce32bd83b96
42ceaf16-00f1-8076-87e8-5ce32bd83b96
ed92b016-00f1-8076-87e8-5ce32bd83b96
e25ab116-00f1-8076-87e8-5ce32bd83b96

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: