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)

01a11314-7523-789c-bf18-8e1a6e9c0994
01a11314-7523-7a25-b689-3777cdb6af45
01a11314-7523-7b61-aeda-01d72f7a6fa1
01a11314-7523-7c7f-b13c-4cb90ba16c55
01a11314-7523-7d96-9044-bbc98ee0f926
01a11314-7523-7ead-9e8a-11d9219e59f6
01a11314-7523-7fbf-83d0-a6c37f7ce998
01a11314-7524-70d5-8c7a-ce5e995701dc
01a11314-7524-71e8-94b9-dd90e13fe9ad
01a11314-7524-7307-9d49-d231c0b6f58b
01a11314-7524-7421-a987-28eec987391a
01a11314-7524-7534-b5e8-dbb4400e0317
01a11314-7524-764a-956c-bc5877a77efc
01a11314-7524-775d-94f8-90d63a5d1332
01a11314-7524-7873-8021-a4e22d3ba528

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)

1f1c1cb6-2a12-677c-851a-4cf95d479851
1f1c1cb6-2a12-697a-851a-4cf95d479851
1f1c1cb6-2a12-6a6a-851a-4cf95d479851
1f1c1cb6-2a12-6b50-851a-4cf95d479851
1f1c1cb6-2a12-6c22-851a-4cf95d479851
1f1c1cb6-2a12-6cf4-851a-4cf95d479851
1f1c1cb6-2a12-6dbc-851a-4cf95d479851
1f1c1cb6-2a12-6e84-851a-4cf95d479851
1f1c1cb6-2a12-6f56-851a-4cf95d479851
1f1c1cb6-2a13-601e-851a-4cf95d479851
1f1c1cb6-2a13-6172-851a-4cf95d479851
1f1c1cb6-2a13-624e-851a-4cf95d479851
1f1c1cb6-2a13-6316-851a-4cf95d479851
1f1c1cb6-2a13-63e8-851a-4cf95d479851
1f1c1cb6-2a13-64b0-851a-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)

62a13596-c1cb-11f1-851a-4cf95d479851
62a135fa-c1cb-11f1-851a-4cf95d479851
62a13668-c1cb-11f1-851a-4cf95d479851
62a136cc-c1cb-11f1-851a-4cf95d479851
62a13730-c1cb-11f1-851a-4cf95d479851
62a13794-c1cb-11f1-851a-4cf95d479851
62a13802-c1cb-11f1-851a-4cf95d479851
62a1387a-c1cb-11f1-851a-4cf95d479851
62a138de-c1cb-11f1-851a-4cf95d479851
62a13942-c1cb-11f1-851a-4cf95d479851
62a139a6-c1cb-11f1-851a-4cf95d479851
62a13a0a-c1cb-11f1-851a-4cf95d479851
62a13a6e-c1cb-11f1-851a-4cf95d479851
62a13ad2-c1cb-11f1-851a-4cf95d479851
62a13b36-c1cb-11f1-851a-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)

59c73f32-fe04-8711-87ea-5ce32bd83b97
a9f44032-fe04-8711-87ea-5ce32bd83b97
18824132-fe04-8711-87ea-5ce32bd83b97
d9004232-fe04-8711-87ea-5ce32bd83b97
8c754332-fe04-8711-87ea-5ce32bd83b97
e6d04432-fe04-8711-87ea-5ce32bd83b97
b1ed4532-fe04-8711-87ea-5ce32bd83b97
1dfb4632-fe04-8711-87ea-5ce32bd83b97
c3d34732-fe04-8711-87ea-5ce32bd83b97
42754832-fe04-8711-87ea-5ce32bd83b97
58704932-fe04-8711-87ea-5ce32bd83b97
83264a32-fe04-8711-87ea-5ce32bd83b97
6dcf4b32-fe04-8711-87ea-5ce32bd83b97
f6e04c32-fe04-8711-87ea-5ce32bd83b97
d33a4d32-fe04-8711-87ea-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)

bcd8e899-181d-48c1-af2e-941c2136ddb8
c82fb0f3-8449-4959-abc0-562b3d1790d7
e86c4b32-7569-4278-acad-bc63e7bc79fd
3d8c8e7d-e5e0-4170-9a15-080ee3c8fb5f
e3eab9b7-e921-4c76-b345-f7d36e56a59c
05fcbd24-1d23-494d-9825-62585d1ae0a3
7b178a3c-70c4-4182-8be3-e7d1ff4b2bdd
b2674d9c-5aed-41ca-b0cb-ca4997e6c3da
69e46f9d-2b9c-400b-8cf9-5c1320cf8e8a
7cc618c3-66ec-4f86-8350-dec9a631b271
20b8b6c7-2d6c-445e-b40c-27f6a193c972
c8839ee5-1e82-406e-beee-145e74787937
fa84c45f-fc00-48a7-88f6-61f1c09b8ba5
91a51f9a-9153-4c37-8cb2-ab9f666f39a8
dedfb7d6-7813-48ac-88d5-f0bf94037bf5

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: