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)

01a0dc09-e597-767f-9404-9add00d4b59a
01a0dc09-e597-7884-90f2-f74beb52063a
01a0dc09-e597-79c3-8ee6-9b132d42915d
01a0dc09-e597-7ade-a353-d5b8a5d08d6d
01a0dc09-e597-7bf4-afe9-d821abc8dbb3
01a0dc09-e597-7d07-8388-35166fa9c4c7
01a0dc09-e597-7e1d-b028-eddf3d27656d
01a0dc09-e597-7f34-aec6-dd2c22444a06
01a0dc09-e598-704a-ba1b-0e7d8d4ecf85
01a0dc09-e598-7161-b499-f0e98102e826
01a0dc09-e598-7277-9fe2-113966678698
01a0dc09-e598-738e-b19c-1aac8e4cbe59
01a0dc09-e598-74b5-9ad8-576a0a10ad3f
01a0dc09-e598-75e8-b16c-39dff749d9d2
01a0dc09-e598-76fe-a7f4-e81370072511

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)

1f1b9655-619d-6706-b123-4cf95d479851
1f1b9655-619d-68c8-b123-4cf95d479851
1f1b9655-619d-69b8-b123-4cf95d479851
1f1b9655-619d-6a80-b123-4cf95d479851
1f1b9655-619d-6b52-b123-4cf95d479851
1f1b9655-619d-6c1a-b123-4cf95d479851
1f1b9655-619d-6cd8-b123-4cf95d479851
1f1b9655-619d-6daa-b123-4cf95d479851
1f1b9655-619d-6e68-b123-4cf95d479851
1f1b9655-619d-6f30-b123-4cf95d479851
1f1b9655-619e-607a-b123-4cf95d479851
1f1b9655-619e-6188-b123-4cf95d479851
1f1b9655-619e-62e6-b123-4cf95d479851
1f1b9655-619e-644e-b123-4cf95d479851
1f1b9655-619e-6598-b123-4cf95d479851

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)

5619e732-b965-11f1-b123-4cf95d479851
5619e7d2-b965-11f1-b123-4cf95d479851
5619e854-b965-11f1-b123-4cf95d479851
5619e8e0-b965-11f1-b123-4cf95d479851
5619e958-b965-11f1-b123-4cf95d479851
5619e9da-b965-11f1-b123-4cf95d479851
5619ea84-b965-11f1-b123-4cf95d479851
5619eb1a-b965-11f1-b123-4cf95d479851
5619ebb0-b965-11f1-b123-4cf95d479851
5619ec46-b965-11f1-b123-4cf95d479851
5619ecd2-b965-11f1-b123-4cf95d479851
5619ed68-b965-11f1-b123-4cf95d479851
5619edf4-b965-11f1-b123-4cf95d479851
5619ee80-b965-11f1-b123-4cf95d479851
5619ef20-b965-11f1-b123-4cf95d479851

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)

060f420b-2001-8d10-87ea-5ce32bd83b97
58a4430b-2001-8d10-87ea-5ce32bd83b97
5601440b-2001-8d10-87ea-5ce32bd83b97
ce1f450b-2001-8d10-87ea-5ce32bd83b97
1b09460b-2001-8d10-87ea-5ce32bd83b97
6dcf470b-2001-8d10-87ea-5ce32bd83b97
3489480b-2001-8d10-87ea-5ce32bd83b97
653b490b-2001-8d10-87ea-5ce32bd83b97
17ea4a0b-2001-8d10-87ea-5ce32bd83b97
449e4b0b-2001-8d10-87ea-5ce32bd83b97
005a4c0b-2001-8d10-87ea-5ce32bd83b97
5f814d0b-2001-8d10-87ea-5ce32bd83b97
b6b14e0b-2001-8d10-87ea-5ce32bd83b97
46584f0b-2001-8d10-87ea-5ce32bd83b97
9ba0500b-2001-8d10-87ea-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)

1ba156c8-66f1-473a-b872-4dc6430c3768
be97c9a8-1e4f-430f-9d9c-f889692a38fe
cf9611cd-c133-4492-b8d1-9e6ac89d2f09
2d571d36-002c-4732-bb19-b8d631c969fe
daf92de6-1115-4b4d-a2e3-981f2ec80e82
5ca2ebe7-ceaf-46bd-9728-ac78daaeb8b1
bc53370b-c151-401b-b3ed-f45ee8c321b6
37a6797e-4cc5-409e-aee8-7f5742ffc5d8
64e030f2-b68e-4c02-bffb-c073ca929de4
5f2e8088-fec4-49bc-8b49-47e54b066090
d0b5ebd1-763d-43cc-8059-b59da393d1d3
aa6b9606-f0a3-4741-ba22-9b049921de56
1121e127-4c10-4c97-8523-257ef502bc61
6dfc5c3f-fb07-4b99-aae7-f67d348a1897
ef2ccf6c-caf9-48e3-8d38-14de583b096d

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: