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)

019bdca5-919a-7ec1-b1d5-54000df81234
019bdca5-919b-705f-9a44-580d0f1b3cb4
019bdca5-919b-71a2-afa6-0d95b73da31a
019bdca5-919b-72c1-b3ca-5d0c481a8608
019bdca5-919b-73e0-ae1d-e9aebfad8642
019bdca5-919b-74f6-a72d-2cad2888be8a
019bdca5-919b-7611-bd9a-c3945e0354ae
019bdca5-919b-7727-8f76-f6484b0a0355
019bdca5-919b-7842-a5a1-70d971b405e7
019bdca5-919b-795d-a2f6-9b19f1bcbe50
019bdca5-919b-7a77-851b-d5196bb3b502
019bdca5-919b-7b92-a61e-b54fd1d60711
019bdca5-919b-7ca8-98f5-1d43a9956120
019bdca5-919b-7dbf-bccf-7296f76d2719
019bdca5-919b-7ede-91fa-71cbe73d496f

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)

1f0f62d1-7092-6054-9262-4cf95d479851
1f0f62d1-7092-61f8-9262-4cf95d479851
1f0f62d1-7092-62e8-9262-4cf95d479851
1f0f62d1-7092-63b0-9262-4cf95d479851
1f0f62d1-7092-6482-9262-4cf95d479851
1f0f62d1-7092-6540-9262-4cf95d479851
1f0f62d1-7092-6608-9262-4cf95d479851
1f0f62d1-7092-66c6-9262-4cf95d479851
1f0f62d1-7092-6784-9262-4cf95d479851
1f0f62d1-7092-6842-9262-4cf95d479851
1f0f62d1-7092-6978-9262-4cf95d479851
1f0f62d1-7092-6a4a-9262-4cf95d479851
1f0f62d1-7092-6b08-9262-4cf95d479851
1f0f62d1-7092-6bd0-9262-4cf95d479851
1f0f62d1-7092-6cb6-9262-4cf95d479851

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)

02f5ef60-1fc8-44bc-9862-a9c2867f0768
b29407c1-2899-40e8-bff3-f9b9078fb4cb
c490b97b-3ff2-458b-8bce-33f1452a3a78
7d8bdb9a-a323-4777-9f5f-7fef50c29c0b
56bfdd0a-f2bb-42dd-b51d-40de61bc7c1c
1e6e0c2d-8c3c-46ae-8715-ecb580588f77
3588b175-659b-4fc3-9bbc-a243af70a28c
d8cc4b71-fb85-4a53-ae58-ae999cf9ab89
83573a32-1c95-4810-97b1-5a390c804d07
50d06c59-e190-4061-a904-ef826057fb7e
ef273fb6-956f-4f43-8ffe-658aca8f9ccd
a9c34f4d-2575-4d2c-b12a-1c5122159c75
05b99cfc-4957-432a-b2f4-5e4f533b9ce7
1a77fc58-417d-4cb7-b38e-6885c65b5358
1fc010ec-d24b-4cdb-b08d-d3e08008d9cb

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)

170931ca-f62d-11f0-9262-4cf95d479851
17093238-f62d-11f0-9262-4cf95d479851
170932a6-f62d-11f0-9262-4cf95d479851
1709330a-f62d-11f0-9262-4cf95d479851
17093378-f62d-11f0-9262-4cf95d479851
1709345e-f62d-11f0-9262-4cf95d479851
170934cc-f62d-11f0-9262-4cf95d479851
17093530-f62d-11f0-9262-4cf95d479851
17093594-f62d-11f0-9262-4cf95d479851
170935f8-f62d-11f0-9262-4cf95d479851
1709365c-f62d-11f0-9262-4cf95d479851
170936b6-f62d-11f0-9262-4cf95d479851
1709371a-f62d-11f0-9262-4cf95d479851
1709377e-f62d-11f0-9262-4cf95d479851
170937ec-f62d-11f0-9262-4cf95d479851

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)

04d2e410-5004-8401-87ea-5ce32bd83b97
5418e510-5004-8401-87ea-5ce32bd83b97
4451e610-5004-8401-87ea-5ce32bd83b97
77fde710-5004-8401-87ea-5ce32bd83b97
f99de810-5004-8401-87ea-5ce32bd83b97
8f39e910-5004-8401-87ea-5ce32bd83b97
3fe4ea10-5004-8401-87ea-5ce32bd83b97
d75feb10-5004-8401-87ea-5ce32bd83b97
9cf0ec10-5004-8401-87ea-5ce32bd83b97
6c09ed10-5004-8401-87ea-5ce32bd83b97
8dcfee10-5004-8401-87ea-5ce32bd83b97
fc10ef10-5004-8401-87ea-5ce32bd83b97
0e6ff010-5004-8401-87ea-5ce32bd83b97
00b6f110-5004-8401-87ea-5ce32bd83b97
97e4f210-5004-8401-87ea-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: