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)

018f2315-2609-71a6-8f92-19b0312eaef2
018f2315-2609-734c-8f6d-db2ccd49c725
018f2315-2609-7490-85c8-d1d4078157dc
018f2315-2609-75b7-ac3c-6d385fecc16b
018f2315-2609-76d5-a64d-12f0a9230435
018f2315-2609-77f0-b367-33f73d9d0fc4
018f2315-2609-790b-ab41-e20cd31c1722
018f2315-2609-7a29-8565-727fa01fc77b
018f2315-2609-7b48-af94-a4f1f665e76e
018f2315-2609-7c67-9050-55edcaeb4dea
018f2315-2609-7d82-b529-87f6d53dc997
018f2315-2609-7e9c-9516-0fd67df16dc9
018f2315-2609-7fbb-b08e-bd879b9b103b
018f2315-260a-70da-b8bd-1c9d16e67063
018f2315-260a-71fc-9fd3-d3bb3485cd40

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)

1ef051c7-d9f2-6f7e-89b7-4cf95d479851
1ef051c7-d9f3-612c-89b7-4cf95d479851
1ef051c7-d9f3-6226-89b7-4cf95d479851
1ef051c7-d9f3-62ee-89b7-4cf95d479851
1ef051c7-d9f3-63b6-89b7-4cf95d479851
1ef051c7-d9f3-647e-89b7-4cf95d479851
1ef051c7-d9f3-6546-89b7-4cf95d479851
1ef051c7-d9f3-660e-89b7-4cf95d479851
1ef051c7-d9f3-66cc-89b7-4cf95d479851
1ef051c7-d9f3-678a-89b7-4cf95d479851
1ef051c7-d9f3-6910-89b7-4cf95d479851
1ef051c7-d9f3-6a6e-89b7-4cf95d479851
1ef051c7-d9f3-6b5e-89b7-4cf95d479851
1ef051c7-d9f3-6c1c-89b7-4cf95d479851
1ef051c7-d9f3-6cda-89b7-4cf95d479851

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)

345f7d65-1b53-4cc4-80fe-776d7d2f9e6d
53a4c7e8-1bca-4695-8c4e-f114181cd373
3a886019-fa19-4222-b9aa-6c8176985320
97c3a7bb-ffb6-413d-ae66-82efbbc0cb15
b04d45b2-e617-4ec3-926d-0752100946e0
e3576367-bc3d-488c-942e-2ad828cd48d1
dd1ff58a-126e-4054-9c68-10511777b43c
8c9eb660-374c-45b4-92f7-989c575b5380
79505af6-34c7-4980-9b23-784b00e28df9
8291cf52-d4eb-44a7-89ce-9d28fce2e184
95cc0db0-0181-4a36-9c22-f0952ab6bd39
875d4b74-f748-4e24-b6fa-ca9e16915a8e
3a9420b3-48db-42fa-8159-0b2216a72644
0e8adbbe-743b-4daa-a37a-535a9a794077
abc43d1f-1082-4d3b-b270-a312fb5c8233

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)

7d9f4216-051c-11ef-89b7-4cf95d479851
7d9f427a-051c-11ef-89b7-4cf95d479851
7d9f42de-051c-11ef-89b7-4cf95d479851
7d9f4342-051c-11ef-89b7-4cf95d479851
7d9f43a6-051c-11ef-89b7-4cf95d479851
7d9f440a-051c-11ef-89b7-4cf95d479851
7d9f4478-051c-11ef-89b7-4cf95d479851
7d9f44dc-051c-11ef-89b7-4cf95d479851
7d9f454a-051c-11ef-89b7-4cf95d479851
7d9f45ae-051c-11ef-89b7-4cf95d479851
7d9f461c-051c-11ef-89b7-4cf95d479851
7d9f4680-051c-11ef-89b7-4cf95d479851
7d9f46e4-051c-11ef-89b7-4cf95d479851
7d9f473e-051c-11ef-89b7-4cf95d479851
7d9f47ac-051c-11ef-89b7-4cf95d479851

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)

4e30a813-012f-8077-87e8-5ce32bd83b96
92a5a913-012f-8077-87e8-5ce32bd83b96
f38baa13-012f-8077-87e8-5ce32bd83b96
84fcab13-012f-8077-87e8-5ce32bd83b96
64f1ac13-012f-8077-87e8-5ce32bd83b96
b827ad13-012f-8077-87e8-5ce32bd83b96
de21ae13-012f-8077-87e8-5ce32bd83b96
3ac3af13-012f-8077-87e8-5ce32bd83b96
7321b013-012f-8077-87e8-5ce32bd83b96
8739b113-012f-8077-87e8-5ce32bd83b96
6738b213-012f-8077-87e8-5ce32bd83b96
6efdb313-012f-8077-87e8-5ce32bd83b96
dc9cb513-012f-8077-87e8-5ce32bd83b96
b44cb613-012f-8077-87e8-5ce32bd83b96
8d06b713-012f-8077-87e8-5ce32bd83b96

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: