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)

019e8002-1e7c-760d-b620-edc1c13f2973
019e8002-1e7c-7857-a04c-88674a257975
019e8002-1e7c-79cf-bd29-0451ff1942a6
019e8002-1e7c-7b1f-87de-85b86f5ec594
019e8002-1e7c-7c63-81c8-73b15bcff04e
019e8002-1e7c-7daa-a4b9-02824a1036ca
019e8002-1e7c-7eee-8a37-868eadcf5247
019e8002-1e7d-703a-bd7e-13e4f686cfb4
019e8002-1e7d-717d-8f56-c32a913f1a95
019e8002-1e7d-72c1-91f8-c718f7084924
019e8002-1e7d-7405-9404-3caa629c24e5
019e8002-1e7d-7548-b60b-eccbf3ac4430
019e8002-1e7d-769c-a6c5-676d89db6a12
019e8002-1e7d-77e8-8f37-b946c8020caf
019e8002-1e7d-7934-8a86-d9974e97b8b4

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)

1f15d3a6-6484-6ebe-b344-4cf95d479851
1f15d3a6-6485-6184-b344-4cf95d479851
1f15d3a6-6485-633c-b344-4cf95d479851
1f15d3a6-6485-64d6-b344-4cf95d479851
1f15d3a6-6485-665c-b344-4cf95d479851
1f15d3a6-6485-67d8-b344-4cf95d479851
1f15d3a6-6485-694a-b344-4cf95d479851
1f15d3a6-6485-6ac6-b344-4cf95d479851
1f15d3a6-6485-6c38-b344-4cf95d479851
1f15d3a6-6485-6daa-b344-4cf95d479851
1f15d3a6-6485-6ff8-b344-4cf95d479851
1f15d3a6-6486-6174-b344-4cf95d479851
1f15d3a6-6486-62d2-b344-4cf95d479851
1f15d3a6-6486-6444-b344-4cf95d479851
1f15d3a6-6486-65b6-b344-4cf95d479851

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)

66486750-5d3a-11f1-b344-4cf95d479851
664867fa-5d3a-11f1-b344-4cf95d479851
6648689a-5d3a-11f1-b344-4cf95d479851
66486930-5d3a-11f1-b344-4cf95d479851
664869d0-5d3a-11f1-b344-4cf95d479851
66486a70-5d3a-11f1-b344-4cf95d479851
66486b1a-5d3a-11f1-b344-4cf95d479851
66486bb0-5d3a-11f1-b344-4cf95d479851
66486c5a-5d3a-11f1-b344-4cf95d479851
66486d7c-5d3a-11f1-b344-4cf95d479851
66486e08-5d3a-11f1-b344-4cf95d479851
66486e8a-5d3a-11f1-b344-4cf95d479851
66486f20-5d3a-11f1-b344-4cf95d479851
66486fca-5d3a-11f1-b344-4cf95d479851
6648704c-5d3a-11f1-b344-4cf95d479851

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)

18431203-1d05-8709-87ea-5ce32bd83b97
c9ef1303-1d05-8709-87ea-5ce32bd83b97
024a1403-1d05-8709-87ea-5ce32bd83b97
99df1503-1d05-8709-87ea-5ce32bd83b97
32701603-1d05-8709-87ea-5ce32bd83b97
1baa1703-1d05-8709-87ea-5ce32bd83b97
44ed1803-1d05-8709-87ea-5ce32bd83b97
105f1903-1d05-8709-87ea-5ce32bd83b97
5b051a03-1d05-8709-87ea-5ce32bd83b97
fe141b03-1d05-8709-87ea-5ce32bd83b97
eab21c03-1d05-8709-87ea-5ce32bd83b97
61ba1d03-1d05-8709-87ea-5ce32bd83b97
df401e03-1d05-8709-87ea-5ce32bd83b97
33111f03-1d05-8709-87ea-5ce32bd83b97
30402003-1d05-8709-87ea-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)

26ab1c0e-f926-41a0-9826-fb53a591f1d5
37a72774-a86e-437f-8487-f6abae9b297d
f0ae2705-9471-4a4f-84a6-7d77b14a3864
87448eda-eaa9-4f2c-ad04-3f50ad6f3c19
e9148818-9fbe-464a-a4fc-a9ccec553a1e
1ca31c87-5787-43da-87ac-c6e3ff7528fa
2eb07551-99de-43e2-9c30-efa4b668c3d8
d20599f6-018e-4154-abd8-e2f09e8e1add
3997ab37-913c-4e6d-8e20-c8299c760cf9
ecb82818-0c3e-46cc-9a06-ec799a1f5fdd
ea6b65a4-8ddd-454e-81d4-af185cdd5d6c
12f1eed6-6a59-4a2e-9b21-6124e3d71f29
9bb1d7d6-320d-4fa1-9889-05a084192795
ec8141eb-74fd-449b-a298-5a0cb234d847
ca82f244-7dac-46cf-a6c1-5e2e190c8458

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: