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)

0195f4be-afe7-766f-b154-0c913c4eab7e
0195f4be-afe7-7825-84b0-6e9e0457c36c
0195f4be-afe7-7969-bbd7-8ac42ee95305
0195f4be-afe7-7a88-aed4-26c325474773
0195f4be-afe7-7ba2-8750-47c363b3d115
0195f4be-afe7-7cb9-905a-a232adda0955
0195f4be-afe7-7dd3-ba28-08663d5f7841
0195f4be-afe7-7eea-afbf-424c0817720d
0195f4be-afe7-7000-ad8e-d647b58fd04a
0195f4be-afe8-7088-8de4-2990bc0dbc5f
0195f4be-afe8-71bb-af5b-6f70a4219c61
0195f4be-afe8-72d1-849c-2c50b971fcc1
0195f4be-afe8-73e8-8d62-32d3533ba066
0195f4be-afe8-7503-8fcf-ea54f7b28a2d
0195f4be-afe8-7619-81a7-ccbe2c516976

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)

1f00f7a6-c38a-6940-8a93-4cf95d479851
1f00f7a6-c38a-6ada-8a93-4cf95d479851
1f00f7a6-c38a-6bc0-8a93-4cf95d479851
1f00f7a6-c38a-6c92-8a93-4cf95d479851
1f00f7a6-c38a-6d50-8a93-4cf95d479851
1f00f7a6-c38a-6e0e-8a93-4cf95d479851
1f00f7a6-c38a-6ec2-8a93-4cf95d479851
1f00f7a6-c38a-6f80-8a93-4cf95d479851
1f00f7a6-c38b-6034-8a93-4cf95d479851
1f00f7a6-c38b-60f2-8a93-4cf95d479851
1f00f7a6-c38b-6232-8a93-4cf95d479851
1f00f7a6-c38b-62fa-8a93-4cf95d479851
1f00f7a6-c38b-63ae-8a93-4cf95d479851
1f00f7a6-c38b-6462-8a93-4cf95d479851
1f00f7a6-c38b-6516-8a93-4cf95d479851

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)

f977d67d-046e-41e6-a9de-94823fef3f7d
c102e48d-cabf-420e-9d79-57c94d88d676
33b94fc1-c282-49ae-aaac-dae75d44c593
25930fe5-c033-4ed3-bd3f-c070c96d7730
9933f9f7-f90d-48ef-88aa-70129db87989
db1d22df-ba92-472c-919b-049bbf96dcbd
09bef8e8-bcff-4cc0-8279-0c968c48143d
a02b5bce-33d7-4c78-b583-22847ce734a4
a1a22824-ef88-44c0-b2e5-5ea2baf2e0f2
d9ce9b80-1f94-4e53-bf09-1423f3172b5e
aa1d4391-04dc-4583-8188-5fe892fccddd
7f266440-b325-4946-a80b-aa201e82cd9e
85c36ee0-1538-4d6e-b99f-8d633a333ee9
91212870-00eb-4051-9624-d1f6ecd20a95
b5802fb2-1615-40e1-86e0-5ed800866e9d

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)

6c38ba3e-0f7a-11f0-8a93-4cf95d479851
6c38baa2-0f7a-11f0-8a93-4cf95d479851
6c38bb06-0f7a-11f0-8a93-4cf95d479851
6c38bb6a-0f7a-11f0-8a93-4cf95d479851
6c38bbce-0f7a-11f0-8a93-4cf95d479851
6c38bc32-0f7a-11f0-8a93-4cf95d479851
6c38bc8c-0f7a-11f0-8a93-4cf95d479851
6c38bce6-0f7a-11f0-8a93-4cf95d479851
6c38bd40-0f7a-11f0-8a93-4cf95d479851
6c38bd9a-0f7a-11f0-8a93-4cf95d479851
6c38bdfe-0f7a-11f0-8a93-4cf95d479851
6c38be58-0f7a-11f0-8a93-4cf95d479851
6c38beb2-0f7a-11f0-8a93-4cf95d479851
6c38bf0c-0f7a-11f0-8a93-4cf95d479851
6c38bf66-0f7a-11f0-8a93-4cf95d479851

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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

b1677534-0109-805c-87e9-5ce32bd83b96
1b737634-0109-805c-87e9-5ce32bd83b96
67d07734-0109-805c-87e9-5ce32bd83b96
b25c7834-0109-805c-87e9-5ce32bd83b96
0d8d7934-0109-805c-87e9-5ce32bd83b96
cfb47a34-0109-805c-87e9-5ce32bd83b96
4ae97b34-0109-805c-87e9-5ce32bd83b96
23377c34-0109-805c-87e9-5ce32bd83b96
c71a7d34-0109-805c-87e9-5ce32bd83b96
14cd7e34-0109-805c-87e9-5ce32bd83b96
42e47f34-0109-805c-87e9-5ce32bd83b96
072c8034-0109-805c-87e9-5ce32bd83b96
e4248134-0109-805c-87e9-5ce32bd83b96
86ee8234-0109-805c-87e9-5ce32bd83b96
df278334-0109-805c-87e9-5ce32bd83b96

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: