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)

019e8002-265c-7e73-b906-a3ea55d58235
019e8002-265c-7005-a5da-59e3926e63cb
019e8002-265d-7140-a4ff-f53522de1303
019e8002-265d-725f-9b7b-b11d41e6c6f4
019e8002-265d-7375-8b37-d71106bee40e
019e8002-265d-748c-9e3e-7c8a9f8e6481
019e8002-265d-75af-b050-fb52986ebaf2
019e8002-265d-76c1-80f3-e59a7431d5e6
019e8002-265d-77d8-8d22-84eab30ced5f
019e8002-265d-7917-8135-edfc460f508b
019e8002-265d-7a32-bcbd-c1e63645e0a3
019e8002-265d-7b54-bc5d-9e6c74dbf11e
019e8002-265d-7c67-8e9d-c3a59ca535ce
019e8002-265d-7d79-8628-70c1f0b0a0b3
019e8002-265d-7e8c-89f1-9db3e5bc4078

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)

1f15d3a6-77bf-686c-b344-4cf95d479851
1f15d3a6-77bf-6ac4-b344-4cf95d479851
1f15d3a6-77bf-6c0e-b344-4cf95d479851
1f15d3a6-77bf-6cd6-b344-4cf95d479851
1f15d3a6-77bf-6d9e-b344-4cf95d479851
1f15d3a6-77bf-6e5c-b344-4cf95d479851
1f15d3a6-77bf-6f1a-b344-4cf95d479851
1f15d3a6-77bf-6fd8-b344-4cf95d479851
1f15d3a6-77c0-6096-b344-4cf95d479851
1f15d3a6-77c0-6154-b344-4cf95d479851
1f15d3a6-77c0-629e-b344-4cf95d479851
1f15d3a6-77c0-6366-b344-4cf95d479851
1f15d3a6-77c0-6424-b344-4cf95d479851
1f15d3a6-77c0-64f6-b344-4cf95d479851
1f15d3a6-77c0-65be-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)

677c0690-5d3a-11f1-b344-4cf95d479851
677c06fe-5d3a-11f1-b344-4cf95d479851
677c0762-5d3a-11f1-b344-4cf95d479851
677c07c6-5d3a-11f1-b344-4cf95d479851
677c082a-5d3a-11f1-b344-4cf95d479851
677c088e-5d3a-11f1-b344-4cf95d479851
677c08f2-5d3a-11f1-b344-4cf95d479851
677c0956-5d3a-11f1-b344-4cf95d479851
677c09c4-5d3a-11f1-b344-4cf95d479851
677c0a32-5d3a-11f1-b344-4cf95d479851
677c0afa-5d3a-11f1-b344-4cf95d479851
677c0b9a-5d3a-11f1-b344-4cf95d479851
677c0c08-5d3a-11f1-b344-4cf95d479851
677c0c76-5d3a-11f1-b344-4cf95d479851
677c0cda-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)

f56f1605-1d05-8709-87ea-5ce32bd83b97
190d1705-1d05-8709-87ea-5ce32bd83b97
b2f01805-1d05-8709-87ea-5ce32bd83b97
2bde1905-1d05-8709-87ea-5ce32bd83b97
57f71a05-1d05-8709-87ea-5ce32bd83b97
f5211b05-1d05-8709-87ea-5ce32bd83b97
1f091c05-1d05-8709-87ea-5ce32bd83b97
61bf1d05-1d05-8709-87ea-5ce32bd83b97
ef7a1e05-1d05-8709-87ea-5ce32bd83b97
46091f05-1d05-8709-87ea-5ce32bd83b97
e4562005-1d05-8709-87ea-5ce32bd83b97
f1f82105-1d05-8709-87ea-5ce32bd83b97
3ef42205-1d05-8709-87ea-5ce32bd83b97
c9732305-1d05-8709-87ea-5ce32bd83b97
5a4c2505-1d05-8709-87ea-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)

66cb1c7b-9598-4d6c-83f4-fa3b59b6cf7c
9d8aeda6-9967-41f7-b996-862391942452
8faf57f9-dc83-4370-94df-da9aa33848d1
e10b8649-2969-4ef0-8056-78682a4dc1aa
5c7c676b-7310-41ad-b27d-2081920a1c45
defa0e4e-3058-4aeb-a88f-26dd686660c0
edbc24d7-e54f-4d10-a95c-71c4515ce244
9bf02b35-7908-4366-aa5f-fb865b9a7b8f
f370a379-edaf-4bbc-8ac5-aa255368b606
48958a83-a240-4d54-ba29-59d2ebee7a3b
4ad493d6-b785-4920-a821-647ba941fbc7
7c68a0b5-b77a-4716-a805-6f2a7eeed369
d7e10189-844f-4904-ab49-1c243915ee68
8c38f0f1-15eb-4de1-bfb7-adcd0218b4aa
d5db7225-081e-4439-a6ec-8d2e28835e32

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: