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)

01a084f4-a7d2-718e-83f2-6cda9467afd2
01a084f4-a7d3-73aa-ac48-43e2bf392ea1
01a084f4-a7d3-74f6-aaef-40ebb0cf8205
01a084f4-a7d3-7611-8d35-78d68386b137
01a084f4-a7d3-7727-8929-9d3c598562eb
01a084f4-a7d3-7842-a77a-1203177302d6
01a084f4-a7d3-7959-a1c7-cec2e7ba061a
01a084f4-a7d3-7a6f-b24e-7819de32a484
01a084f4-a7d3-7b86-8407-f0e9f111d19f
01a084f4-a7d3-7c98-aa51-d1efa66e0912
01a084f4-a7d3-7daf-88e8-0ab5e05cd46f
01a084f4-a7d3-7ec1-876b-f8dd96b02d82
01a084f4-a7d3-7fd3-bbf4-14fa6eb447e0
01a084f4-a7d4-70e6-9490-5213208394df
01a084f4-a7d4-71f8-aab5-0fa50a99f897

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)

1f1ac1ba-85f0-6010-a923-4cf95d479851
1f1ac1ba-85f0-6344-a923-4cf95d479851
1f1ac1ba-85f0-6448-a923-4cf95d479851
1f1ac1ba-85f0-6510-a923-4cf95d479851
1f1ac1ba-85f0-65ce-a923-4cf95d479851
1f1ac1ba-85f0-6696-a923-4cf95d479851
1f1ac1ba-85f0-675e-a923-4cf95d479851
1f1ac1ba-85f0-6826-a923-4cf95d479851
1f1ac1ba-85f0-68e4-a923-4cf95d479851
1f1ac1ba-85f0-69ac-a923-4cf95d479851
1f1ac1ba-85f0-6b28-a923-4cf95d479851
1f1ac1ba-85f0-6bfa-a923-4cf95d479851
1f1ac1ba-85f0-6cae-a923-4cf95d479851
1f1ac1ba-85f0-6d76-a923-4cf95d479851
1f1ac1ba-85f0-6ede-a923-4cf95d479851

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)

a85f0fec-ac1b-11f1-a923-4cf95d479851
a85f105a-ac1b-11f1-a923-4cf95d479851
a85f10c8-ac1b-11f1-a923-4cf95d479851
a85f1136-ac1b-11f1-a923-4cf95d479851
a85f11a4-ac1b-11f1-a923-4cf95d479851
a85f1208-ac1b-11f1-a923-4cf95d479851
a85f126c-ac1b-11f1-a923-4cf95d479851
a85f12c6-ac1b-11f1-a923-4cf95d479851
a85f132a-ac1b-11f1-a923-4cf95d479851
a85f138e-ac1b-11f1-a923-4cf95d479851
a85f13e8-ac1b-11f1-a923-4cf95d479851
a85f144c-ac1b-11f1-a923-4cf95d479851
a85f14b0-ac1b-11f1-a923-4cf95d479851
a85f1514-ac1b-11f1-a923-4cf95d479851
a85f1578-ac1b-11f1-a923-4cf95d479851

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)

2b056801-a201-8c0f-87ea-5ce32bd83b97
2c906901-a201-8c0f-87ea-5ce32bd83b97
de4f6a01-a201-8c0f-87ea-5ce32bd83b97
ecd26b01-a201-8c0f-87ea-5ce32bd83b97
a95f6c01-a201-8c0f-87ea-5ce32bd83b97
59116e01-a201-8c0f-87ea-5ce32bd83b97
802a6f01-a201-8c0f-87ea-5ce32bd83b97
a6307001-a201-8c0f-87ea-5ce32bd83b97
c1f37101-a201-8c0f-87ea-5ce32bd83b97
cda27201-a201-8c0f-87ea-5ce32bd83b97
67dc7301-a201-8c0f-87ea-5ce32bd83b97
9dd37401-a201-8c0f-87ea-5ce32bd83b97
92b67501-a201-8c0f-87ea-5ce32bd83b97
2b467601-a201-8c0f-87ea-5ce32bd83b97
62f17701-a201-8c0f-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)

950f1037-2327-4e18-aaba-66d52dccd4f9
f70ca96f-4c4a-4ecd-ab22-b0dc456fe736
8e7d7e4d-0ab2-4c82-8b71-d40665a9e9e4
64021b6c-297f-4c36-9d6a-6e32160e73a2
d0c626e8-fc84-4b45-b4c1-94a60f5cad4d
25450967-eb0d-4523-b63c-e65321d20384
f1cdd280-accf-44b4-8335-69df97992f08
24ad5261-1476-4a51-b497-80c21cd26ceb
cc58e6d8-fbc6-4835-9d59-698ff7f3fbfb
c1460984-d1da-4bb5-ae15-f01e1d12afa6
d7ab71e7-0587-40c2-b861-e59fa37ad987
c2450014-0adc-484a-ad30-8f790b4b5ed3
9799259d-1581-4ef0-9b14-a785f30e2400
2abaa0f0-1627-4a0b-b1b5-477a67a0b3cd
53e9b935-c5af-46ed-aa51-f15c60a023f4

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: