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)

019c9dfa-63bd-7205-a2f8-8e1882d00376
019c9dfa-63bd-73bf-b5ea-e475366273c9
019c9dfa-63bd-7503-a8d7-e580468d68da
019c9dfa-63bd-7621-b281-391573d251dc
019c9dfa-63bd-773c-af6c-874b1605f90e
019c9dfa-63bd-7857-9e6b-c40334dcaa80
019c9dfa-63bd-796d-b738-5ceb7dae27de
019c9dfa-63bd-7a84-85fc-8be3bc0555a3
019c9dfa-63bd-7bdc-9b25-1208818a3c5d
019c9dfa-63bd-7cfa-bd7e-b0ac7ef25d73
019c9dfa-63bd-7e11-ac00-f5e60694cf0d
019c9dfa-63bd-7f27-a128-53d4684c6a8b
019c9dfa-63be-703e-90e8-5a495b71da63
019c9dfa-63be-7159-b4bc-96b0af1ed470
019c9dfa-63be-7273-ab86-9e0d099b4e9a

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)

1f113ad1-8597-69d4-82cb-4cf95d479851
1f113ad1-8597-6b8c-82cb-4cf95d479851
1f113ad1-8597-6c72-82cb-4cf95d479851
1f113ad1-8597-6d44-82cb-4cf95d479851
1f113ad1-8597-6e02-82cb-4cf95d479851
1f113ad1-8597-6eca-82cb-4cf95d479851
1f113ad1-8597-6f88-82cb-4cf95d479851
1f113ad1-8598-6046-82cb-4cf95d479851
1f113ad1-8598-6118-82cb-4cf95d479851
1f113ad1-8598-61e0-82cb-4cf95d479851
1f113ad1-8598-632a-82cb-4cf95d479851
1f113ad1-8598-63fc-82cb-4cf95d479851
1f113ad1-8598-64ba-82cb-4cf95d479851
1f113ad1-8598-6582-82cb-4cf95d479851
1f113ad1-8598-6640-82cb-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)

3a8f030d-08e0-470b-8924-e9b2e0c741f4
f5125729-0c0b-49a0-88ab-0b3b4e04374c
a4bae985-f450-458a-ab4c-790463c72c35
c93e7522-f715-47a6-98ef-5bc47f43f11f
99001933-da77-4742-b4db-7c6f067a2f07
8ef5e302-4098-49a2-807c-ada069c73406
c66eca6d-3059-4b8a-a9dd-4b03d7ae43e9
b13f8aae-ea8a-4aeb-9c3d-189a18ad986b
fc64c836-000f-4cec-a181-66c9992296af
b2e00868-dd4e-49b9-b8cf-e295a5480756
96aca87b-11f6-4df9-8a60-5f1b377b0f48
869e5ba9-96d9-4a07-b83f-061392b0df31
450d59fb-974e-41db-9057-0bf73a8ca1ee
8a93bd22-1fb0-43a9-8dbe-4f5ff0e06d28
11af603b-44c0-4bbd-966d-930f20c881e9

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)

18598b54-13ad-11f1-82cb-4cf95d479851
18598bb8-13ad-11f1-82cb-4cf95d479851
18598c1c-13ad-11f1-82cb-4cf95d479851
18598c80-13ad-11f1-82cb-4cf95d479851
18598ce4-13ad-11f1-82cb-4cf95d479851
18598d48-13ad-11f1-82cb-4cf95d479851
18598da2-13ad-11f1-82cb-4cf95d479851
18598dfc-13ad-11f1-82cb-4cf95d479851
18598e60-13ad-11f1-82cb-4cf95d479851
18598ec4-13ad-11f1-82cb-4cf95d479851
18598f1e-13ad-11f1-82cb-4cf95d479851
18598f78-13ad-11f1-82cb-4cf95d479851
18598fdc-13ad-11f1-82cb-4cf95d479851
18599036-13ad-11f1-82cb-4cf95d479851
18599090-13ad-11f1-82cb-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)

b97c6626-bb01-8a03-87ea-5ce32bd83b97
88386726-bb01-8a03-87ea-5ce32bd83b97
dc166826-bb01-8a03-87ea-5ce32bd83b97
446a6926-bb01-8a03-87ea-5ce32bd83b97
09196a26-bb01-8a03-87ea-5ce32bd83b97
74506b26-bb01-8a03-87ea-5ce32bd83b97
736d6c26-bb01-8a03-87ea-5ce32bd83b97
15586d26-bb01-8a03-87ea-5ce32bd83b97
8c256e26-bb01-8a03-87ea-5ce32bd83b97
82fc6f26-bb01-8a03-87ea-5ce32bd83b97
641a7026-bb01-8a03-87ea-5ce32bd83b97
98e37126-bb01-8a03-87ea-5ce32bd83b97
6d8b7226-bb01-8a03-87ea-5ce32bd83b97
24b17326-bb01-8a03-87ea-5ce32bd83b97
a5067426-bb01-8a03-87ea-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: