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)

019cbacf-806d-7d7d-98b5-5497a4290c0a
019cbacf-806d-7f0f-966b-d43d46ea6558
019cbacf-806e-7052-9da8-cfc3162284e3
019cbacf-806e-7175-8635-5cc06d9b15d9
019cbacf-806e-7294-a300-0ca56455b8e5
019cbacf-806e-73b3-aac7-7fc3166ce7aa
019cbacf-806e-74c9-a697-1ade9c6c083c
019cbacf-806e-75e4-9f1c-1531ec7283c8
019cbacf-806e-76fe-9bba-bbe3fecba0b7
019cbacf-806e-7815-aad2-64f5d40b2bbb
019cbacf-806e-7930-a393-fdac89eb50ce
019cbacf-806e-7a4e-8ce9-63bf93aa5b99
019cbacf-806e-7b65-84d1-771f4ab0edf6
019cbacf-806e-7c7f-aeb1-ff1490c0e911
019cbacf-806e-7d96-9df9-b8a60d06c72c

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)

1f118135-d0a2-6dde-8c82-4cf95d479851
1f118135-d0a2-6f82-8c82-4cf95d479851
1f118135-d0a3-6068-8c82-4cf95d479851
1f118135-d0a3-613a-8c82-4cf95d479851
1f118135-d0a3-620c-8c82-4cf95d479851
1f118135-d0a3-62d4-8c82-4cf95d479851
1f118135-d0a3-639c-8c82-4cf95d479851
1f118135-d0a3-6464-8c82-4cf95d479851
1f118135-d0a3-6522-8c82-4cf95d479851
1f118135-d0a3-65ea-8c82-4cf95d479851
1f118135-d0a3-672a-8c82-4cf95d479851
1f118135-d0a3-6806-8c82-4cf95d479851
1f118135-d0a3-68c4-8c82-4cf95d479851
1f118135-d0a3-698c-8c82-4cf95d479851
1f118135-d0a3-6a4a-8c82-4cf95d479851

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)

a8086e7f-75df-419b-a8d9-fad1e3f95dcd
041e37a5-a858-4291-9468-95aa46b283ed
00b4ec19-4044-4825-bd40-9d82a92daa28
80448511-daf4-4f62-aea0-6dcc2d1cc945
c38a8d44-cc4f-4094-ae8c-a74b7393666a
fe8905cb-ffd7-45f9-86ca-6c6d1749738b
3e3b807f-0147-4e9e-a946-0e998c300f32
316f0159-dbac-435c-8fa2-797b6a1881f5
2bcda88a-60e0-4b83-91dc-bbaeaf70c420
4ac30282-587b-4d77-ac07-521074032332
1c2a738b-b60f-4c4d-bae6-87bfef2d9903
cdbc5ffd-293e-4e85-8762-759078b0bb6b
ce44de02-7783-407d-afd8-51613bde8e80
6bb18e10-612f-4b73-899a-acd2c336be50
0f23c598-168d-4cd3-802b-9f65feda10c4

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)

5d0a4008-1813-11f1-8c82-4cf95d479851
5d0a406c-1813-11f1-8c82-4cf95d479851
5d0a40d0-1813-11f1-8c82-4cf95d479851
5d0a413e-1813-11f1-8c82-4cf95d479851
5d0a41a2-1813-11f1-8c82-4cf95d479851
5d0a4210-1813-11f1-8c82-4cf95d479851
5d0a4274-1813-11f1-8c82-4cf95d479851
5d0a42d8-1813-11f1-8c82-4cf95d479851
5d0a433c-1813-11f1-8c82-4cf95d479851
5d0a43a0-1813-11f1-8c82-4cf95d479851
5d0a43fa-1813-11f1-8c82-4cf95d479851
5d0a445e-1813-11f1-8c82-4cf95d479851
5d0a44b8-1813-11f1-8c82-4cf95d479851
5d0a4512-1813-11f1-8c82-4cf95d479851
5d0a4576-1813-11f1-8c82-4cf95d479851

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)

995af52e-1905-8f03-87ea-5ce32bd83b97
447cf62e-1905-8f03-87ea-5ce32bd83b97
35f4f72e-1905-8f03-87ea-5ce32bd83b97
ea58f82e-1905-8f03-87ea-5ce32bd83b97
3300f92e-1905-8f03-87ea-5ce32bd83b97
f464fa2e-1905-8f03-87ea-5ce32bd83b97
48a3fb2e-1905-8f03-87ea-5ce32bd83b97
1779fc2e-1905-8f03-87ea-5ce32bd83b97
698dfd2e-1905-8f03-87ea-5ce32bd83b97
5a46fe2e-1905-8f03-87ea-5ce32bd83b97
39bd002f-1905-8f03-87ea-5ce32bd83b97
51f8012f-1905-8f03-87ea-5ce32bd83b97
549e022f-1905-8f03-87ea-5ce32bd83b97
b9b6032f-1905-8f03-87ea-5ce32bd83b97
7b92042f-1905-8f03-87ea-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: