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)

01a024e0-53f7-7ade-bc16-2279f8868fbb
01a024e0-53f7-7cda-a087-c8e765fbe3f0
01a024e0-53f7-7e19-a7a8-b9ef0368ee91
01a024e0-53f7-7f34-9b90-fddd194669a9
01a024e0-53f8-704a-baa0-88662412fecb
01a024e0-53f8-7161-8b6d-1898a19f2a4e
01a024e0-53f8-7273-9e8c-60102ef57345
01a024e0-53f8-738a-b4a3-c2e92a0ef47a
01a024e0-53f8-74a0-9ef2-bec414a9e3fe
01a024e0-53f8-75b3-82f2-4cd8d3204931
01a024e0-53f8-76c9-b0f1-6371454aa019
01a024e0-53f8-77e0-8530-562b36718a50
01a024e0-53f8-78f2-a49d-87fad6f9a435
01a024e0-53f8-7a05-abd2-2ec690eb7957
01a024e0-53f8-7b17-b60c-5c0036aca137

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)

1f19d728-e516-68a0-a0f5-4cf95d479851
1f19d728-e516-6a6c-a0f5-4cf95d479851
1f19d728-e516-6b52-a0f5-4cf95d479851
1f19d728-e516-6c24-a0f5-4cf95d479851
1f19d728-e516-6cec-a0f5-4cf95d479851
1f19d728-e516-6daa-a0f5-4cf95d479851
1f19d728-e516-6e68-a0f5-4cf95d479851
1f19d728-e516-6f30-a0f5-4cf95d479851
1f19d728-e516-6fee-a0f5-4cf95d479851
1f19d728-e517-60ac-a0f5-4cf95d479851
1f19d728-e517-61f6-a0f5-4cf95d479851
1f19d728-e517-62c8-a0f5-4cf95d479851
1f19d728-e517-6386-a0f5-4cf95d479851
1f19d728-e517-6444-a0f5-4cf95d479851
1f19d728-e517-6502-a0f5-4cf95d479851

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)

8e5175de-9d72-11f1-a0f5-4cf95d479851
8e51764c-9d72-11f1-a0f5-4cf95d479851
8e5176ba-9d72-11f1-a0f5-4cf95d479851
8e517728-9d72-11f1-a0f5-4cf95d479851
8e5177f0-9d72-11f1-a0f5-4cf95d479851
8e517872-9d72-11f1-a0f5-4cf95d479851
8e5178e0-9d72-11f1-a0f5-4cf95d479851
8e517944-9d72-11f1-a0f5-4cf95d479851
8e5179bc-9d72-11f1-a0f5-4cf95d479851
8e517a20-9d72-11f1-a0f5-4cf95d479851
8e517a8e-9d72-11f1-a0f5-4cf95d479851
8e517af2-9d72-11f1-a0f5-4cf95d479851
8e517b60-9d72-11f1-a0f5-4cf95d479851
8e517bc4-9d72-11f1-a0f5-4cf95d479851
8e517c28-9d72-11f1-a0f5-4cf95d479851

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)

910c7910-9003-890e-87ea-5ce32bd83b97
38807a10-9003-890e-87ea-5ce32bd83b97
95657b10-9003-890e-87ea-5ce32bd83b97
82f27c10-9003-890e-87ea-5ce32bd83b97
1bd57d10-9003-890e-87ea-5ce32bd83b97
a76f7e10-9003-890e-87ea-5ce32bd83b97
29bb7f10-9003-890e-87ea-5ce32bd83b97
06c28010-9003-890e-87ea-5ce32bd83b97
d95e8110-9003-890e-87ea-5ce32bd83b97
a7718210-9003-890e-87ea-5ce32bd83b97
17d68310-9003-890e-87ea-5ce32bd83b97
29b78410-9003-890e-87ea-5ce32bd83b97
cbc08510-9003-890e-87ea-5ce32bd83b97
41f38610-9003-890e-87ea-5ce32bd83b97
6cd28710-9003-890e-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)

a2886299-f1ae-4fc2-9b8a-6dd52c4dcc41
a0487721-5f69-49ff-a67e-4822452c9df5
68609be9-ea18-4672-a154-a9f0d8f450d7
83cccaf9-f62c-40b5-9a71-c89be4b5f7d8
df72bf1c-245e-4bbf-a46c-536086f7a03b
bd0de496-364c-44df-8586-4cbca8ee5c25
1043b4b7-76ae-4e6a-8804-79988d444e76
4c11765d-15a5-4b60-ab9e-fce0b49d5faf
335c5816-965f-4053-a181-f519caf72c4f
719a84cc-d455-44d7-a74f-58feb644badc
521197b9-1b1f-4b0d-9beb-e75d9d4d64b0
dd26c714-8d14-4e25-9e93-086582521000
6bd56836-ffb0-4d28-9ac0-c7b2fb76ed3b
02f68deb-ff61-4e37-94fa-f9e755691324
066cedd3-6764-4c21-9d4a-ed98665be5e6

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: