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)

019dd6ad-ffac-7c11-bda5-c7b5d42445ef
019dd6ad-ffac-7da6-8998-1384c94f30f2
019dd6ad-ffac-7eea-9eaf-8432bb4e3bc0
019dd6ad-ffac-700d-875e-451bc7d9c15c
019dd6ad-ffad-7127-ad0b-ca5e54afcd23
019dd6ad-ffad-7242-a96b-4a989a4694c6
019dd6ad-ffad-735d-ad7e-348466c344ae
019dd6ad-ffad-747b-afcd-a2c731d1a617
019dd6ad-ffad-7592-a93d-b06dc9480aca
019dd6ad-ffad-76b1-8997-632a7c4bf975
019dd6ad-ffad-77cb-9621-0697b7d90066
019dd6ad-ffad-78e6-a91f-ea2d3400330f
019dd6ad-ffad-7a00-9917-037115f4254f
019dd6ad-ffad-7b3c-afda-0d96a9872694
019dd6ad-ffad-7c88-9c0d-a7c89a20023b

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)

1f143640-054b-689e-90bd-4cf95d479851
1f143640-054b-6a4c-90bd-4cf95d479851
1f143640-054b-6b3c-90bd-4cf95d479851
1f143640-054b-6c0e-90bd-4cf95d479851
1f143640-054b-6cd6-90bd-4cf95d479851
1f143640-054b-6d9e-90bd-4cf95d479851
1f143640-054b-6e66-90bd-4cf95d479851
1f143640-054b-6f24-90bd-4cf95d479851
1f143640-054b-6fec-90bd-4cf95d479851
1f143640-054c-60aa-90bd-4cf95d479851
1f143640-054c-6208-90bd-4cf95d479851
1f143640-054c-62e4-90bd-4cf95d479851
1f143640-054c-63ac-90bd-4cf95d479851
1f143640-054c-647e-90bd-4cf95d479851
1f143640-054c-655a-90bd-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)

1745f584-d51b-410d-a0b2-cc178ba10d59
4c52c6c0-040f-46aa-9ce9-c6c86d725248
31f34b20-9897-4513-91be-d7fe4633116e
8a4f66aa-7c94-48dc-8d98-dbc8c92056a3
9d549f0b-c3df-428f-a883-d3af1649aa3d
6b9d2523-f3bf-4177-ab75-787ae83c15e5
c1824516-71a4-4ef7-8fc3-26c035a16ecd
c818070e-329b-4a89-8f51-ad1df91642e0
518d919c-77b4-4b24-9a19-695a21d0b653
375173ca-b2bb-4f85-9876-eb833e89c95a
3a450e54-4d67-420c-a646-ae020ef25579
5fc9c437-3a79-4d30-b841-7f37ef558e37
fa279216-e61e-4481-8e43-73fc2b4a7916
1cc3c54b-2551-4c11-a61a-7370cae61b21
a4994b58-dd9e-4e52-9b26-58feb743ab5e

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)

0054ca82-4364-11f1-90bd-4cf95d479851
0054cae6-4364-11f1-90bd-4cf95d479851
0054cb40-4364-11f1-90bd-4cf95d479851
0054cba4-4364-11f1-90bd-4cf95d479851
0054cbfe-4364-11f1-90bd-4cf95d479851
0054cc62-4364-11f1-90bd-4cf95d479851
0054ccd0-4364-11f1-90bd-4cf95d479851
0054cd34-4364-11f1-90bd-4cf95d479851
0054cd8e-4364-11f1-90bd-4cf95d479851
0054cdf2-4364-11f1-90bd-4cf95d479851
0054ce4c-4364-11f1-90bd-4cf95d479851
0054ceb0-4364-11f1-90bd-4cf95d479851
0054cf0a-4364-11f1-90bd-4cf95d479851
0054cf6e-4364-11f1-90bd-4cf95d479851
0054cfc8-4364-11f1-90bd-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)

f20aa714-2900-8707-87ea-5ce32bd83b97
163aa814-2900-8707-87ea-5ce32bd83b97
0189a914-2900-8707-87ea-5ce32bd83b97
0869aa14-2900-8707-87ea-5ce32bd83b97
7bf3ab14-2900-8707-87ea-5ce32bd83b97
2d7bac14-2900-8707-87ea-5ce32bd83b97
4082ad14-2900-8707-87ea-5ce32bd83b97
6d84ae14-2900-8707-87ea-5ce32bd83b97
d56caf14-2900-8707-87ea-5ce32bd83b97
b1f6b014-2900-8707-87ea-5ce32bd83b97
bf30b114-2900-8707-87ea-5ce32bd83b97
b45cb214-2900-8707-87ea-5ce32bd83b97
2dccb314-2900-8707-87ea-5ce32bd83b97
b648b414-2900-8707-87ea-5ce32bd83b97
e998b614-2900-8707-87ea-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: