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)

019c7ee2-379e-73e4-a6d0-fef8a5837260
019c7ee2-379e-759a-9be6-b443578458b2
019c7ee2-379e-7730-9459-7c32a18f38d9
019c7ee2-379e-78a4-b6dd-1efbac8fe3eb
019c7ee2-379e-79e0-bceb-efe6f642f61e
019c7ee2-379e-7b44-b136-6994f26f9249
019c7ee2-379e-7cb1-9883-d918fe39cae4
019c7ee2-379e-7df8-b3b8-2f93c8f3a36e
019c7ee2-379e-7f44-9b11-0d9e494e0169
019c7ee2-379f-70b5-a39b-e486f3239975
019c7ee2-379f-7205-974b-8905491a77be
019c7ee2-379f-7340-b79a-258579a14ea3
019c7ee2-379f-74a4-8757-326801dc2f6d
019c7ee2-379f-7611-af9c-11ee99a83141
019c7ee2-379f-7759-8fd9-3b17f2a14519

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)

1f10eee7-81e0-6c22-9168-4cf95d479851
1f10eee7-81e0-6e98-9168-4cf95d479851
1f10eee7-81e0-6fc4-9168-4cf95d479851
1f10eee7-81e1-6096-9168-4cf95d479851
1f10eee7-81e1-61fe-9168-4cf95d479851
1f10eee7-81e1-6398-9168-4cf95d479851
1f10eee7-81e1-6528-9168-4cf95d479851
1f10eee7-81e1-66ae-9168-4cf95d479851
1f10eee7-81e1-6834-9168-4cf95d479851
1f10eee7-81e1-69c4-9168-4cf95d479851
1f10eee7-81e1-6c08-9168-4cf95d479851
1f10eee7-81e1-6d0c-9168-4cf95d479851
1f10eee7-81e1-6dde-9168-4cf95d479851
1f10eee7-81e1-6f14-9168-4cf95d479851
1f10eee7-81e2-6090-9168-4cf95d479851

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)

acece509-98b4-4d78-82c8-f11ba7a7695c
7262a83a-532b-4dca-ab15-6aef3d3002ad
db06fb86-480c-4c04-bf4f-2a1b7b5c92a2
11b90e47-9a22-4e09-8165-96decb8d15d4
0aaf68b1-2643-4016-837f-fe9801b01f9b
ee09cf9d-6c6f-4f6c-95ee-400f0acb37e4
a22d88fb-7ef6-4bfd-ac83-57c56525981d
3a20868a-69ff-481a-90d9-5da560a0b888
16476e88-d8e5-49eb-b2ea-0d09b715ad54
f0a51621-64b9-4b99-b545-adc214d1eb83
7ea510fc-c1ad-4b9f-92b6-992fa0bf5501
67807f66-98dc-4a59-a544-4c0761c504cc
e81468ba-a750-49f6-9ff6-a37fa9662f66
f0764537-54c6-46b6-bbf0-1e2b30682061
72d0da5b-d5f1-4df6-b707-05a8d290fa29

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)

781e27f2-0eee-11f1-9168-4cf95d479851
781e289c-0eee-11f1-9168-4cf95d479851
781e2932-0eee-11f1-9168-4cf95d479851
781e29d2-0eee-11f1-9168-4cf95d479851
781e2a54-0eee-11f1-9168-4cf95d479851
781e2ab8-0eee-11f1-9168-4cf95d479851
781e2b26-0eee-11f1-9168-4cf95d479851
781e2b8a-0eee-11f1-9168-4cf95d479851
781e2bee-0eee-11f1-9168-4cf95d479851
781e2c7a-0eee-11f1-9168-4cf95d479851
781e2d10-0eee-11f1-9168-4cf95d479851
781e2db0-0eee-11f1-9168-4cf95d479851
781e2eb4-0eee-11f1-9168-4cf95d479851
781e2f68-0eee-11f1-9168-4cf95d479851
781e2ff4-0eee-11f1-9168-4cf95d479851

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)

f0408b00-8501-8403-87ea-5ce32bd83b97
53858c00-8501-8403-87ea-5ce32bd83b97
63238d00-8501-8403-87ea-5ce32bd83b97
6a478e00-8501-8403-87ea-5ce32bd83b97
85a38f00-8501-8403-87ea-5ce32bd83b97
c7c49000-8501-8403-87ea-5ce32bd83b97
96d29100-8501-8403-87ea-5ce32bd83b97
f6069200-8501-8403-87ea-5ce32bd83b97
18d69300-8501-8403-87ea-5ce32bd83b97
225c9400-8501-8403-87ea-5ce32bd83b97
9f3c9500-8501-8403-87ea-5ce32bd83b97
e8559600-8501-8403-87ea-5ce32bd83b97
aa239700-8501-8403-87ea-5ce32bd83b97
fc729800-8501-8403-87ea-5ce32bd83b97
f6f29900-8501-8403-87ea-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: