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)

01a15a26-c455-72ee-be6a-7f2d8599bcda
01a15a26-c455-7436-84dc-6c3e70a552b7
01a15a26-c455-7579-8c72-75d7aa1a0d4d
01a15a26-c455-7694-8e9b-d9d2184e9418
01a15a26-c455-77aa-ab3b-dc05b1ab4e79
01a15a26-c455-78bd-b976-10dd546ab155
01a15a26-c455-79d3-88d7-9c8792a77a41
01a15a26-c455-7ae6-8aa1-86038fadc51b
01a15a26-c455-7bf8-9b9a-0ddcc0ab3927
01a15a26-c455-7d0b-be55-ba6121c8287a
01a15a26-c455-7e21-bc82-314b8cf2063f
01a15a26-c455-7f34-92e1-1336968fa0f9
01a15a26-c456-704a-8ae6-02f57419e55a
01a15a26-c456-715d-ba3d-ec88225612a7
01a15a26-c456-7273-9d17-ae524ad52204

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)

1f1cca39-dd6a-691a-b835-4cf95d479851
1f1cca39-dd6a-6abe-b835-4cf95d479851
1f1cca39-dd6a-6ba4-b835-4cf95d479851
1f1cca39-dd6a-6c76-b835-4cf95d479851
1f1cca39-dd6a-6d3e-b835-4cf95d479851
1f1cca39-dd6a-6e10-b835-4cf95d479851
1f1cca39-dd6a-6ece-b835-4cf95d479851
1f1cca39-dd6a-6f96-b835-4cf95d479851
1f1cca39-dd6b-605e-b835-4cf95d479851
1f1cca39-dd6b-6126-b835-4cf95d479851
1f1cca39-dd6b-6266-b835-4cf95d479851
1f1cca39-dd6b-6342-b835-4cf95d479851
1f1cca39-dd6b-6400-b835-4cf95d479851
1f1cca39-dd6b-64c8-b835-4cf95d479851
1f1cca39-dd6b-6590-b835-4cf95d479851

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)

9dd6b66c-cca3-11f1-b835-4cf95d479851
9dd6b6d0-cca3-11f1-b835-4cf95d479851
9dd6b734-cca3-11f1-b835-4cf95d479851
9dd6b798-cca3-11f1-b835-4cf95d479851
9dd6b7fc-cca3-11f1-b835-4cf95d479851
9dd6b860-cca3-11f1-b835-4cf95d479851
9dd6b8c4-cca3-11f1-b835-4cf95d479851
9dd6b93c-cca3-11f1-b835-4cf95d479851
9dd6b9a0-cca3-11f1-b835-4cf95d479851
9dd6b9fa-cca3-11f1-b835-4cf95d479851
9dd6ba5e-cca3-11f1-b835-4cf95d479851
9dd6bac2-cca3-11f1-b835-4cf95d479851
9dd6bb26-cca3-11f1-b835-4cf95d479851
9dd6bb8a-cca3-11f1-b835-4cf95d479851
9dd6bbee-cca3-11f1-b835-4cf95d479851

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)

daf08034-df03-8512-87ea-5ce32bd83b97
b57d8134-df03-8512-87ea-5ce32bd83b97
cfdb8234-df03-8512-87ea-5ce32bd83b97
69278334-df03-8512-87ea-5ce32bd83b97
43358434-df03-8512-87ea-5ce32bd83b97
5f7e8534-df03-8512-87ea-5ce32bd83b97
cb1c8734-df03-8512-87ea-5ce32bd83b97
58168834-df03-8512-87ea-5ce32bd83b97
4ef58934-df03-8512-87ea-5ce32bd83b97
c50c8a34-df03-8512-87ea-5ce32bd83b97
ce428b34-df03-8512-87ea-5ce32bd83b97
190d8c34-df03-8512-87ea-5ce32bd83b97
b7b48d34-df03-8512-87ea-5ce32bd83b97
dcc78e34-df03-8512-87ea-5ce32bd83b97
6b608f34-df03-8512-87ea-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)

8cf7ef55-6319-4950-aa80-c968399255f3
9c660ca8-d75a-484e-97c7-bc0deacfa9c6
61d54b27-d0e3-4445-8232-650a60246895
b1168564-43f7-4fdd-8785-b66591746da3
c87f2907-84f7-4c3a-92e8-34a1a62f1c06
c1b10860-c8e1-4cae-a511-2f0b3d1f9ec6
8cf49893-75d3-400a-85e2-3b1de14e92fc
5803d334-4ba1-48ba-84b3-ef72da429b22
43dc1c8f-5420-4e84-b31a-c9d09cc22327
04f2ad83-bda4-4986-97ee-90214169cd05
189b714c-b3bb-488d-b0e4-d689f4c10376
6a0703af-8110-49ee-ac81-1280d3b6a046
c9731862-49b0-4d61-b729-ae3fb9e2da2f
62044b61-7b9a-4427-8866-96ffc41fac0c
90569c64-4374-4d30-8198-5150f21b32f0

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: