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)

019c942d-b84e-7f71-b390-e5aa3ac8306b
019c942d-b84f-710f-8518-77803c26c9c9
019c942d-b84f-7252-95a5-ed6d8410ddd1
019c942d-b84f-7371-9253-d8e3e7133977
019c942d-b84f-748c-982d-950324c66979
019c942d-b84f-75a6-8f4f-6de04d1bccb6
019c942d-b84f-76bd-a95d-47b794a3cc47
019c942d-b84f-77d3-8558-68a713fbc814
019c942d-b84f-78ee-af85-24a75777bf8e
019c942d-b84f-7a05-92c9-3e559000d63e
019c942d-b84f-7b1f-9ddf-bac174f21619
019c942d-b84f-7c36-9c7a-ff804a5bc681
019c942d-b84f-7d50-9a8f-03bd913f25f4
019c942d-b84f-7e6b-9076-a9592b94872e
019c942d-b84f-7f82-85b8-188b959c5aba

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)

1f1122e4-d70f-678a-a43c-4cf95d479851
1f1122e4-d70f-6924-a43c-4cf95d479851
1f1122e4-d70f-6a0a-a43c-4cf95d479851
1f1122e4-d70f-6adc-a43c-4cf95d479851
1f1122e4-d70f-6ba4-a43c-4cf95d479851
1f1122e4-d70f-6c6c-a43c-4cf95d479851
1f1122e4-d70f-6d34-a43c-4cf95d479851
1f1122e4-d70f-6dfc-a43c-4cf95d479851
1f1122e4-d70f-6eba-a43c-4cf95d479851
1f1122e4-d70f-6f82-a43c-4cf95d479851
1f1122e4-d710-60ea-a43c-4cf95d479851
1f1122e4-d710-61bc-a43c-4cf95d479851
1f1122e4-d710-6284-a43c-4cf95d479851
1f1122e4-d710-6342-a43c-4cf95d479851
1f1122e4-d710-63f6-a43c-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)

cb9afe7e-256c-4f14-b2e2-31b1f48a7298
4be8767b-6474-40aa-b193-9c6752c09c93
07539e80-267f-4310-98c8-50424f61774a
bfeb22d1-5de7-491b-8312-341b3889be2b
23351674-cf8a-41e3-bc16-4dae304bc4a0
b390fcfc-9703-4d6e-b5ad-c2a6d2cf15d1
62e63638-001b-4b91-916a-f3a0a4463bed
82b23f11-7ea3-4047-8db2-3d95f6ab0a58
1356424d-05ac-4935-837f-151804ca8670
23a2257c-e05e-4593-8e32-ecac8c34e13a
ff1f7a29-0e80-4077-9d0c-44bdfe3169f6
102b83a3-26cb-43f0-bed3-cc7360dd82d5
79e1468b-432a-4553-80fc-8b9f0146cf1f
bc8dcb3c-7318-46f5-8240-3fbe123528db
d2e8a9f3-0ddf-41d6-9699-18d24e2ce021

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)

4d710928-122e-11f1-a43c-4cf95d479851
4d710996-122e-11f1-a43c-4cf95d479851
4d7109fa-122e-11f1-a43c-4cf95d479851
4d710a5e-122e-11f1-a43c-4cf95d479851
4d710ab8-122e-11f1-a43c-4cf95d479851
4d710b1c-122e-11f1-a43c-4cf95d479851
4d710b76-122e-11f1-a43c-4cf95d479851
4d710bda-122e-11f1-a43c-4cf95d479851
4d710c3e-122e-11f1-a43c-4cf95d479851
4d710c98-122e-11f1-a43c-4cf95d479851
4d710cfc-122e-11f1-a43c-4cf95d479851
4d710d56-122e-11f1-a43c-4cf95d479851
4d710db0-122e-11f1-a43c-4cf95d479851
4d710e14-122e-11f1-a43c-4cf95d479851
4d710e78-122e-11f1-a43c-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)

c99b391e-4702-8803-87ea-5ce32bd83b97
dc083a1e-4702-8803-87ea-5ce32bd83b97
16293b1e-4702-8803-87ea-5ce32bd83b97
bc603c1e-4702-8803-87ea-5ce32bd83b97
b1fb3e1e-4702-8803-87ea-5ce32bd83b97
171e3f1e-4702-8803-87ea-5ce32bd83b97
a928401e-4702-8803-87ea-5ce32bd83b97
d902411e-4702-8803-87ea-5ce32bd83b97
ee85421e-4702-8803-87ea-5ce32bd83b97
6de1431e-4702-8803-87ea-5ce32bd83b97
222f441e-4702-8803-87ea-5ce32bd83b97
b084451e-4702-8803-87ea-5ce32bd83b97
315f461e-4702-8803-87ea-5ce32bd83b97
6be1471e-4702-8803-87ea-5ce32bd83b97
cc8f481e-4702-8803-87ea-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: