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)

019c8ef8-b80e-79bb-8cf1-3f4758aa2a7a
019c8ef8-b80e-7b9e-9719-d99c9ed48e11
019c8ef8-b80e-7d17-b7ee-028212c8b076
019c8ef8-b80e-7e63-91e6-6f2cd8612f1f
019c8ef8-b80e-7faf-ba0c-786e6e2da369
019c8ef8-b80f-70fe-8ab0-0b2ed99dd250
019c8ef8-b80f-724a-8600-1c4a3bd276f3
019c8ef8-b80f-7392-9328-940c7a178da6
019c8ef8-b80f-74da-8834-7f9a7063a71d
019c8ef8-b80f-761d-b162-1d4f813590ca
019c8ef8-b80f-7761-8efa-0b3fd97c792c
019c8ef8-b80f-78a4-8a60-7b45804a77eb
019c8ef8-b80f-79e8-92d6-15f501dcc70b
019c8ef8-b80f-7b2c-b2c7-fcbe299520c1
019c8ef8-b80f-7c6f-b3d8-8f4575b05691

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)

1f11162e-7172-6cc8-8d42-4cf95d479851
1f11162e-7172-6f48-8d42-4cf95d479851
1f11162e-7173-60ce-8d42-4cf95d479851
1f11162e-7173-6240-8d42-4cf95d479851
1f11162e-7173-639e-8d42-4cf95d479851
1f11162e-7173-64fc-8d42-4cf95d479851
1f11162e-7173-6664-8d42-4cf95d479851
1f11162e-7173-67c2-8d42-4cf95d479851
1f11162e-7173-692a-8d42-4cf95d479851
1f11162e-7173-6a7e-8d42-4cf95d479851
1f11162e-7173-6c72-8d42-4cf95d479851
1f11162e-7173-6dda-8d42-4cf95d479851
1f11162e-7173-6f24-8d42-4cf95d479851
1f11162e-7174-6078-8d42-4cf95d479851
1f11162e-7174-61d6-8d42-4cf95d479851

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)

534c587d-cb84-4725-9d8d-31d22dd25b86
940a3ba7-357f-43cb-9def-7d693d82cfdb
ef35dac4-ea68-4af8-9772-259ed3fcefed
0bf5c2d4-1699-49d0-9c97-19c181c6755f
358c11a7-10ae-4747-8a38-c7788bb3b6dd
2ca9036c-c6ad-410a-b24f-743cb8ec9bad
3537a5ec-fd0d-41e6-becd-a8266ca94d6a
639816d2-9c86-4de4-b94d-64424b5e5d67
0b8ba026-359f-4a11-9cbf-ba52b804c2a4
c0c5daa4-2a56-4a2c-a26c-d1641ab76097
8a22fe52-9d73-4173-b4a0-a46e4e421dd4
de0c7e88-ae5e-46e5-a7c8-e57ca226d3b7
5678a198-526d-488b-abc6-b296a3e5a5e5
247edfc5-c15b-4a56-826b-28f51f3ef35c
3582aa16-0913-430b-8cf0-c601a94325c8

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)

e71748f2-1162-11f1-8d42-4cf95d479851
e7174992-1162-11f1-8d42-4cf95d479851
e7174a32-1162-11f1-8d42-4cf95d479851
e7174ad2-1162-11f1-8d42-4cf95d479851
e7174b72-1162-11f1-8d42-4cf95d479851
e7174c08-1162-11f1-8d42-4cf95d479851
e7174c9e-1162-11f1-8d42-4cf95d479851
e7174d3e-1162-11f1-8d42-4cf95d479851
e7174dd4-1162-11f1-8d42-4cf95d479851
e7174e7e-1162-11f1-8d42-4cf95d479851
e7174f14-1162-11f1-8d42-4cf95d479851
e7174fb4-1162-11f1-8d42-4cf95d479851
e7175054-1162-11f1-8d42-4cf95d479851
e71750ea-1162-11f1-8d42-4cf95d479851
e7175194-1162-11f1-8d42-4cf95d479851

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)

61e0ac1e-3702-8703-87ea-5ce32bd83b97
6a3bad1e-3702-8703-87ea-5ce32bd83b97
a9ecae1e-3702-8703-87ea-5ce32bd83b97
9fc2af1e-3702-8703-87ea-5ce32bd83b97
7cf9b01e-3702-8703-87ea-5ce32bd83b97
73f8b11e-3702-8703-87ea-5ce32bd83b97
7579b21e-3702-8703-87ea-5ce32bd83b97
0823b31e-3702-8703-87ea-5ce32bd83b97
0d2eb41e-3702-8703-87ea-5ce32bd83b97
e4e5b51e-3702-8703-87ea-5ce32bd83b97
128ab61e-3702-8703-87ea-5ce32bd83b97
25bfb71e-3702-8703-87ea-5ce32bd83b97
0117b81e-3702-8703-87ea-5ce32bd83b97
f3c5b91e-3702-8703-87ea-5ce32bd83b97
8b9bba1e-3702-8703-87ea-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: