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)

019acf60-58e6-709c-9b2e-16a0b29a1f19
019acf60-58e6-724e-81d3-74619f286180
019acf60-58e6-7396-b0f8-40b21250142e
019acf60-58e6-74b9-95d5-4dccbfc8808b
019acf60-58e6-75dc-9736-64317b01f751
019acf60-58e6-76f6-b72b-cab308179a4b
019acf60-58e6-7815-8744-8aec80259a89
019acf60-58e6-7930-afbb-fd4c2456b5ab
019acf60-58e6-7a4e-b6cf-2cfb42908790
019acf60-58e6-7b6d-827d-13cb53c361ff
019acf60-58e6-7c88-99f0-5ce56d21b96b
019acf60-58e6-7da2-85aa-47550f62a13e
019acf60-58e6-7ebd-8348-c85091b41114
019acf60-58e6-7fd8-a517-4b40c2b50052
019acf60-58e7-70f2-b3b1-b8530e935cd7

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)

1f0cd16b-7120-65f6-8c9d-4cf95d479851
1f0cd16b-7120-679a-8c9d-4cf95d479851
1f0cd16b-7120-6880-8c9d-4cf95d479851
1f0cd16b-7120-6952-8c9d-4cf95d479851
1f0cd16b-7120-6a1a-8c9d-4cf95d479851
1f0cd16b-7120-6ae2-8c9d-4cf95d479851
1f0cd16b-7120-6ba0-8c9d-4cf95d479851
1f0cd16b-7120-6c68-8c9d-4cf95d479851
1f0cd16b-7120-6d26-8c9d-4cf95d479851
1f0cd16b-7120-6dee-8c9d-4cf95d479851
1f0cd16b-7120-6f24-8c9d-4cf95d479851
1f0cd16b-7121-6000-8c9d-4cf95d479851
1f0cd16b-7121-60be-8c9d-4cf95d479851
1f0cd16b-7121-6186-8c9d-4cf95d479851
1f0cd16b-7121-6244-8c9d-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)

12f207cb-5eca-46f5-90cf-d73ed8f24b91
a78c16af-8f99-45a6-8bae-e7874ebb6b7d
0b09b71f-1c8a-4173-9a61-c6d213e56630
75036447-538f-40d4-9e1b-eae75fcacaa9
8b3c2d2b-a639-40e8-8630-7b2a8f13f038
be21182f-2204-4c18-89ce-dffdfeb1540a
629ee8bf-6079-4b46-a6cc-a2588ce00c3a
0e870d36-065b-43f3-b15f-b944a10a2562
a6ca3312-a9e7-413d-8c79-3531088c234b
c0477187-ae0d-4253-90e3-21d0b828ef1c
a10b3448-d357-4db0-8ac7-b45e6cfae740
e9f05ec1-6a86-4d85-9afb-64461313d871
ff43e27a-2b1e-4b86-89e8-3a2ed8d7bca6
a61045ed-d5bf-42b9-84d8-8c3a00b1504d
37690b3a-2f7c-4aab-8439-18e84ccc52d3

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)

b7121758-cd16-11f0-8c9d-4cf95d479851
b71217c6-cd16-11f0-8c9d-4cf95d479851
b7121834-cd16-11f0-8c9d-4cf95d479851
b7121898-cd16-11f0-8c9d-4cf95d479851
b71218fc-cd16-11f0-8c9d-4cf95d479851
b7121960-cd16-11f0-8c9d-4cf95d479851
b71219c4-cd16-11f0-8c9d-4cf95d479851
b7121a28-cd16-11f0-8c9d-4cf95d479851
b7121a82-cd16-11f0-8c9d-4cf95d479851
b7121af0-cd16-11f0-8c9d-4cf95d479851
b7121b4a-cd16-11f0-8c9d-4cf95d479851
b7121bae-cd16-11f0-8c9d-4cf95d479851
b7121c12-cd16-11f0-8c9d-4cf95d479851
b7121c6c-cd16-11f0-8c9d-4cf95d479851
b7121cd0-cd16-11f0-8c9d-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)

54794931-b202-8d14-87e9-5ce32bd83b97
75374a31-b202-8d14-87e9-5ce32bd83b97
db8d4c31-b202-8d14-87e9-5ce32bd83b97
e3654d31-b202-8d14-87e9-5ce32bd83b97
0d794e31-b202-8d14-87e9-5ce32bd83b97
357a4f31-b202-8d14-87e9-5ce32bd83b97
c9965031-b202-8d14-87e9-5ce32bd83b97
82385131-b202-8d14-87e9-5ce32bd83b97
42d55231-b202-8d14-87e9-5ce32bd83b97
48b95331-b202-8d14-87e9-5ce32bd83b97
5fa95431-b202-8d14-87e9-5ce32bd83b97
76a85531-b202-8d14-87e9-5ce32bd83b97
2c6d5631-b202-8d14-87e9-5ce32bd83b97
16b55731-b202-8d14-87e9-5ce32bd83b97
817e5831-b202-8d14-87e9-5ce32bd83b97

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: