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)

019fcf16-ec67-760d-a9c9-0800324e82ee
019fcf16-ec67-77cf-9ba9-9d4f6b28a9cd
019fcf16-ec67-790b-a66e-40ca08200607
019fcf16-ec67-7a25-8a40-1886a74ff17e
019fcf16-ec67-7b3c-9b69-3961f2d7e91b
019fcf16-ec67-7c4e-9291-9c4bba9e7b72
019fcf16-ec67-7d61-bacf-7793a5c98d70
019fcf16-ec67-7e73-9d2a-df74331f7529
019fcf16-ec67-7f86-a20a-0b5c51f917db
019fcf16-ec68-709c-8bf1-d7ab29771c7d
019fcf16-ec68-71b3-bfc6-0c6167aa9c4e
019fcf16-ec68-72c1-9b26-05d12a7c246f
019fcf16-ec68-73d3-bf13-21722e61d2e4
019fcf16-ec68-74e6-9478-33a835dae02c
019fcf16-ec68-75f8-a7b4-7b3ae41823c2

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)

1f1905b8-2f3f-62a8-a7a6-4cf95d479851
1f1905b8-2f3f-6442-a7a6-4cf95d479851
1f1905b8-2f3f-6528-a7a6-4cf95d479851
1f1905b8-2f3f-65fa-a7a6-4cf95d479851
1f1905b8-2f3f-66c2-a7a6-4cf95d479851
1f1905b8-2f3f-6780-a7a6-4cf95d479851
1f1905b8-2f3f-683e-a7a6-4cf95d479851
1f1905b8-2f3f-68fc-a7a6-4cf95d479851
1f1905b8-2f3f-69ba-a7a6-4cf95d479851
1f1905b8-2f3f-6a78-a7a6-4cf95d479851
1f1905b8-2f3f-6bc2-a7a6-4cf95d479851
1f1905b8-2f3f-6c94-a7a6-4cf95d479851
1f1905b8-2f3f-6d48-a7a6-4cf95d479851
1f1905b8-2f3f-6e06-a7a6-4cf95d479851
1f1905b8-2f3f-6ec4-a7a6-4cf95d479851

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)

82f3ff96-905b-11f1-a7a6-4cf95d479851
82f3fff0-905b-11f1-a7a6-4cf95d479851
82f40054-905b-11f1-a7a6-4cf95d479851
82f400ae-905b-11f1-a7a6-4cf95d479851
82f40112-905b-11f1-a7a6-4cf95d479851
82f40176-905b-11f1-a7a6-4cf95d479851
82f401d0-905b-11f1-a7a6-4cf95d479851
82f40234-905b-11f1-a7a6-4cf95d479851
82f40298-905b-11f1-a7a6-4cf95d479851
82f402fc-905b-11f1-a7a6-4cf95d479851
82f40360-905b-11f1-a7a6-4cf95d479851
82f403c4-905b-11f1-a7a6-4cf95d479851
82f40428-905b-11f1-a7a6-4cf95d479851
82f4048c-905b-11f1-a7a6-4cf95d479851
82f404f0-905b-11f1-a7a6-4cf95d479851

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)

ee5add21-7c05-880d-87ea-5ce32bd83b97
259ade21-7c05-880d-87ea-5ce32bd83b97
e208df21-7c05-880d-87ea-5ce32bd83b97
3adbe021-7c05-880d-87ea-5ce32bd83b97
9391e121-7c05-880d-87ea-5ce32bd83b97
5a8ae221-7c05-880d-87ea-5ce32bd83b97
99d7e321-7c05-880d-87ea-5ce32bd83b97
08f8e421-7c05-880d-87ea-5ce32bd83b97
329fe521-7c05-880d-87ea-5ce32bd83b97
7149e621-7c05-880d-87ea-5ce32bd83b97
67ace721-7c05-880d-87ea-5ce32bd83b97
4ae8e821-7c05-880d-87ea-5ce32bd83b97
72c2e921-7c05-880d-87ea-5ce32bd83b97
88f8ea21-7c05-880d-87ea-5ce32bd83b97
3a27eb21-7c05-880d-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)

c74a6fbb-aaab-4549-9a98-98a3a06ff1a1
ed6b84d2-31ec-4397-8c42-c9ccb5819505
005769a3-8139-4baf-9647-1e476c17af76
c5a09d3b-a9cc-4c4d-b3a9-8c277968c889
ef9da612-1d86-4230-88d7-3e720a398dc5
a5003155-819e-4408-8bd5-da9c3c545707
93522c3f-a8ba-42ee-95c3-ffc911aa1cd9
b82752d5-5f29-43a9-a092-6d61918bc4a7
1a195de0-ecd6-4e75-ad5b-4926e3d649e3
3fd2b564-6b77-41e4-9f68-9955d4a48930
5b783b70-f41d-4b76-9aca-81a770923f01
7a3cdc15-a658-4f94-8d09-3af2ee6d6b61
68f13c7a-893e-46de-8bce-b21d0079a97b
ce97db3f-4838-4ab7-8d20-24efbad38954
e7075946-a3ba-4f46-9c8c-312b017a2bad

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: