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)

019d081d-6704-7a63-a39f-bfd8c7d0e929
019d081d-6704-7bf4-a8a8-d3a03ed5cbbe
019d081d-6704-7d38-98b0-83e04688d6f9
019d081d-6704-7e57-80e6-01e947208277
019d081d-6704-7f71-b1b3-c39d0fc653cd
019d081d-6705-7088-a7b6-71a3eb65b44c
019d081d-6705-71a6-8eaf-0e0f9a4e2576
019d081d-6705-72d1-a1b7-32d8f2cbac1e
019d081d-6705-73f0-a0db-0483973ae070
019d081d-6705-7507-9cd9-0622b8d18e00
019d081d-6705-761d-88e3-fbe8666b2ef6
019d081d-6705-7738-a277-e676dac430de
019d081d-6705-7852-88d1-d26d910f4be3
019d081d-6705-796d-a619-0832444f965e
019d081d-6705-7a84-928c-5054de307698

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)

1f123df1-0099-60ec-aec2-4cf95d479851
1f123df1-0099-627c-aec2-4cf95d479851
1f123df1-0099-636c-aec2-4cf95d479851
1f123df1-0099-643e-aec2-4cf95d479851
1f123df1-0099-6510-aec2-4cf95d479851
1f123df1-0099-65d8-aec2-4cf95d479851
1f123df1-0099-66aa-aec2-4cf95d479851
1f123df1-0099-677c-aec2-4cf95d479851
1f123df1-0099-6844-aec2-4cf95d479851
1f123df1-0099-690c-aec2-4cf95d479851
1f123df1-0099-6a56-aec2-4cf95d479851
1f123df1-0099-6b28-aec2-4cf95d479851
1f123df1-0099-6bfa-aec2-4cf95d479851
1f123df1-0099-6cc2-aec2-4cf95d479851
1f123df1-0099-6d94-aec2-4cf95d479851

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)

8ac3f6eb-ee86-40d3-a18d-ce4e9f25e9b1
2bb66b47-6601-4b1f-b477-bde11510e3d6
a79b4c3a-b730-4362-897d-375340d05f64
52820432-2156-4cac-bacd-a5e2c36c3925
2bc0df52-4112-4580-bf8c-5f31a58affdf
24eb14fe-1ec2-47a4-9676-91a1e3d46d25
efb48b61-6e2f-40fd-9743-601aed75b481
9a2d760e-b67b-4efd-8d5a-b1aa8709c6c9
960683de-7d16-4c06-86a5-3ee94f919747
ef2515ce-47b8-45e3-9482-0ea3e45b6f00
623ba3d1-a4c1-40a1-a951-dff4580448d2
638a812e-c82f-4f0f-96f2-13dd8c64b144
6104c736-5146-453d-9667-7a7560369b5d
5723b622-1cb3-452d-83db-ecdd1e5626d5
aa8ad16b-3255-4b9a-9088-817dd587a568

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)

1009a2c6-23df-11f1-aec2-4cf95d479851
1009a334-23df-11f1-aec2-4cf95d479851
1009a398-23df-11f1-aec2-4cf95d479851
1009a3f2-23df-11f1-aec2-4cf95d479851
1009a460-23df-11f1-aec2-4cf95d479851
1009a4c4-23df-11f1-aec2-4cf95d479851
1009a51e-23df-11f1-aec2-4cf95d479851
1009a582-23df-11f1-aec2-4cf95d479851
1009a5e6-23df-11f1-aec2-4cf95d479851
1009a654-23df-11f1-aec2-4cf95d479851
1009a6b8-23df-11f1-aec2-4cf95d479851
1009a71c-23df-11f1-aec2-4cf95d479851
1009a776-23df-11f1-aec2-4cf95d479851
1009a7da-23df-11f1-aec2-4cf95d479851
1009a83e-23df-11f1-aec2-4cf95d479851

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)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 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) = WRONG!!!
-  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 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)

46f1e425-2905-8e04-87ea-5ce32bd83b97
6e91e525-2905-8e04-87ea-5ce32bd83b97
a76be625-2905-8e04-87ea-5ce32bd83b97
1464e725-2905-8e04-87ea-5ce32bd83b97
5477e825-2905-8e04-87ea-5ce32bd83b97
4ef5e925-2905-8e04-87ea-5ce32bd83b97
d001ea25-2905-8e04-87ea-5ce32bd83b97
c887ec25-2905-8e04-87ea-5ce32bd83b97
b5faed25-2905-8e04-87ea-5ce32bd83b97
6c4cee25-2905-8e04-87ea-5ce32bd83b97
2a0aef25-2905-8e04-87ea-5ce32bd83b97
9c2cf025-2905-8e04-87ea-5ce32bd83b97
a99cf125-2905-8e04-87ea-5ce32bd83b97
7fc0f225-2905-8e04-87ea-5ce32bd83b97
33fff325-2905-8e04-87ea-5ce32bd83b97

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: