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)

019b636f-1dc1-780d-9b91-92cba0951eb9
019b636f-1dc1-7a15-b241-6087c455b0b6
019b636f-1dc1-7b61-87a0-988735613d6e
019b636f-1dc1-7c8c-962b-a6ce1025ee03
019b636f-1dc1-7daf-a073-2297b6b1a99b
019b636f-1dc1-7ed1-b6c6-f8db72fa049e
019b636f-1dc1-7ff8-9cd3-617b49bbf58e
019b636f-1dc2-7144-b93a-c6492d874548
019b636f-1dc2-7294-b11c-7ca1f8ee13c1
019b636f-1dc2-73e8-8c4f-e81bff43fcb0
019b636f-1dc2-7527-8b1b-2be51c4b155e
019b636f-1dc2-7663-ba84-18531204f7ff
019b636f-1dc2-77b7-a896-a7050277d7d5
019b636f-1dc2-78f6-a5c5-8c028720a40d
019b636f-1dc2-7a1d-8e82-92f9f6cb2a7b

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)

1f0e3ae3-7fbc-697e-9439-4cf95d479851
1f0e3ae3-7fbc-6c1c-9439-4cf95d479851
1f0e3ae3-7fbc-6db6-9439-4cf95d479851
1f0e3ae3-7fbc-6f0a-9439-4cf95d479851
1f0e3ae3-7fbd-6072-9439-4cf95d479851
1f0e3ae3-7fbd-6162-9439-4cf95d479851
1f0e3ae3-7fbd-6220-9439-4cf95d479851
1f0e3ae3-7fbd-62e8-9439-4cf95d479851
1f0e3ae3-7fbd-63b0-9439-4cf95d479851
1f0e3ae3-7fbd-646e-9439-4cf95d479851
1f0e3ae3-7fbd-65ae-9439-4cf95d479851
1f0e3ae3-7fbd-6680-9439-4cf95d479851
1f0e3ae3-7fbd-6748-9439-4cf95d479851
1f0e3ae3-7fbd-6806-9439-4cf95d479851
1f0e3ae3-7fbd-68c4-9439-4cf95d479851

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)

c41e915f-94a5-4d79-a8b9-045935af30b2
70f8d3b6-aac1-4eff-b217-b1a9fc2ae3d8
f1e67492-aec3-48cc-b9bb-76c747af0aaf
756296a7-7b6d-4e3d-8e01-8a9cb4f384d7
7eda11c5-614b-4a92-b57e-3d5e59a92955
97c56309-1c8a-4ebb-bbf1-df5d84d46c44
768787d1-9e37-43b5-9ef4-84cdf4493061
e740b575-cb5d-45f7-98dc-2a0bd0a0132c
07bb44a9-a7c3-41be-b522-6a3d4cc3a1c1
6ccc8b21-06cb-4f90-a7e3-10276193d273
26ebb762-2f8d-4496-83ca-17e2797c3752
b06193a1-aac7-4e48-8969-9d7626eea194
cfb94ae6-3151-46f8-a011-03aa231a3001
56bb0196-b16d-4c85-a8af-34ed81563c75
735b00b1-d4e6-42ef-84fd-e756b9a48fe2

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)

37fbddf6-e3ae-11f0-9439-4cf95d479851
37fbde5a-e3ae-11f0-9439-4cf95d479851
37fbdebe-e3ae-11f0-9439-4cf95d479851
37fbe13e-e3ae-11f0-9439-4cf95d479851
37fbe1d4-e3ae-11f0-9439-4cf95d479851
37fbe242-e3ae-11f0-9439-4cf95d479851
37fbe2b0-e3ae-11f0-9439-4cf95d479851
37fbe31e-e3ae-11f0-9439-4cf95d479851
37fbe382-e3ae-11f0-9439-4cf95d479851
37fbe3e6-e3ae-11f0-9439-4cf95d479851
37fbe454-e3ae-11f0-9439-4cf95d479851
37fbe4b8-e3ae-11f0-9439-4cf95d479851
37fbe51c-e3ae-11f0-9439-4cf95d479851
37fbe58a-e3ae-11f0-9439-4cf95d479851
37fbe5e4-e3ae-11f0-9439-4cf95d479851

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)

2327282d-4a01-8a16-87e9-5ce32bd83b97
a005292d-4a01-8a16-87e9-5ce32bd83b97
5f9c2a2d-4a01-8a16-87e9-5ce32bd83b97
b3552b2d-4a01-8a16-87e9-5ce32bd83b97
78222c2d-4a01-8a16-87e9-5ce32bd83b97
10ea2d2d-4a01-8a16-87e9-5ce32bd83b97
2b2c2e2d-4a01-8a16-87e9-5ce32bd83b97
10232f2d-4a01-8a16-87e9-5ce32bd83b97
0fcc302d-4a01-8a16-87e9-5ce32bd83b97
34dd312d-4a01-8a16-87e9-5ce32bd83b97
4f29322d-4a01-8a16-87e9-5ce32bd83b97
496e332d-4a01-8a16-87e9-5ce32bd83b97
b09e342d-4a01-8a16-87e9-5ce32bd83b97
7cf3352d-4a01-8a16-87e9-5ce32bd83b97
b91c362d-4a01-8a16-87e9-5ce32bd83b97

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: