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)

0193aa38-95c0-7a6f-af6a-df8b5ff1b19e
0193aa38-95c0-7c09-ae0e-15866f648d0e
0193aa38-95c0-7d4c-8e3f-00d0d3cde409
0193aa38-95c0-7e6b-9546-db775b35fd8e
0193aa38-95c0-7f86-aebd-c0bd991c9647
0193aa38-95c1-70a0-8dde-2d032997c447
0193aa38-95c1-71bf-8f94-4dd131661798
0193aa38-95c1-72da-a2e6-982cdd2d8b87
0193aa38-95c1-73f0-b2a6-57ccf259b4d7
0193aa38-95c1-750f-9b4f-aaa8b436f434
0193aa38-95c1-7625-930c-2b9f59a28300
0193aa38-95c1-773c-838d-346c7c55e9e8
0193aa38-95c1-7857-8a7a-aaf596291511
0193aa38-95c1-7971-bd23-f967de035afa
0193aa38-95c1-7a8c-b335-e5f5d5274bb1

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)

1efb5fb5-5db2-6282-bb0f-4cf95d479851
1efb5fb5-5db2-6412-bb0f-4cf95d479851
1efb5fb5-5db2-64ee-bb0f-4cf95d479851
1efb5fb5-5db2-65c0-bb0f-4cf95d479851
1efb5fb5-5db2-667e-bb0f-4cf95d479851
1efb5fb5-5db2-673c-bb0f-4cf95d479851
1efb5fb5-5db2-67f0-bb0f-4cf95d479851
1efb5fb5-5db2-68ae-bb0f-4cf95d479851
1efb5fb5-5db2-696c-bb0f-4cf95d479851
1efb5fb5-5db2-6a20-bb0f-4cf95d479851
1efb5fb5-5db2-6b60-bb0f-4cf95d479851
1efb5fb5-5db2-6c28-bb0f-4cf95d479851
1efb5fb5-5db2-6ce6-bb0f-4cf95d479851
1efb5fb5-5db2-6d9a-bb0f-4cf95d479851
1efb5fb5-5db2-6e4e-bb0f-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)

1f61fe56-91ad-429c-98b2-baba0ba12977
11a15056-a3c7-4e29-9abf-714312cf4d7e
e1170640-8cc3-48d7-b3e3-e9c402315071
f96f071b-6189-4b1d-988f-cd7b2e68cf6c
268492d5-58aa-4159-8ef5-f140d6196d9d
26bd13dd-2f71-4c1a-8f8c-fc50f0d3b7a4
daede6c8-f539-4390-9580-6abb0573bac5
c7b6fbe8-68ce-4673-b416-b963f961c709
37f00c6e-58c5-49d8-8087-3c983b8d18ee
8f56edb5-b3f1-4f1b-b0be-f7a1a6794a9c
6d59c7c0-1449-4130-bce0-71a73acc7cdd
d21c799e-def2-4998-80b8-6b61f58f9617
3941d5f8-a380-4ff1-bf83-9f195dd5d598
7b5f954d-2c4e-445a-bd14-6bc87a363ad2
d2565baa-6bc3-4219-afff-5bdbbf2c9a93

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)

55db336c-b5fb-11ef-bb0f-4cf95d479851
55db33d0-b5fb-11ef-bb0f-4cf95d479851
55db343e-b5fb-11ef-bb0f-4cf95d479851
55db3498-b5fb-11ef-bb0f-4cf95d479851
55db3506-b5fb-11ef-bb0f-4cf95d479851
55db3560-b5fb-11ef-bb0f-4cf95d479851
55db35c4-b5fb-11ef-bb0f-4cf95d479851
55db3632-b5fb-11ef-bb0f-4cf95d479851
55db368c-b5fb-11ef-bb0f-4cf95d479851
55db36e6-b5fb-11ef-bb0f-4cf95d479851
55db3740-b5fb-11ef-bb0f-4cf95d479851
55db37a4-b5fb-11ef-bb0f-4cf95d479851
55db37fe-b5fb-11ef-bb0f-4cf95d479851
55db3858-b5fb-11ef-bb0f-4cf95d479851
55db38b2-b5fb-11ef-bb0f-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)

16995c37-01a5-8158-87e8-5ce32bd83b96
b9b55d37-01a5-8158-87e8-5ce32bd83b96
d5a75e37-01a5-8158-87e8-5ce32bd83b96
b9545f37-01a5-8158-87e8-5ce32bd83b96
0ab86037-01a5-8158-87e8-5ce32bd83b96
79a76237-01a5-8158-87e8-5ce32bd83b96
39696337-01a5-8158-87e8-5ce32bd83b96
64c66437-01a5-8158-87e8-5ce32bd83b96
549b6537-01a5-8158-87e8-5ce32bd83b96
33536637-01a5-8158-87e8-5ce32bd83b96
f5ca6737-01a5-8158-87e8-5ce32bd83b96
2da66837-01a5-8158-87e8-5ce32bd83b96
37ac6937-01a5-8158-87e8-5ce32bd83b96
a5de6a37-01a5-8158-87e8-5ce32bd83b96
95d56b37-01a5-8158-87e8-5ce32bd83b96

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: