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)

0198bedc-c95f-762e-9199-8983222d1b93
0198bedc-c95f-77dc-bd7b-2c713af4eaf6
0198bedc-c95f-792c-8278-22bb636f9109
0198bedc-c95f-7a4e-a5da-09a78f02e4a9
0198bedc-c95f-7b6d-abc8-9d2d589c0da6
0198bedc-c95f-7c88-ba62-363f75737d7e
0198bedc-c95f-7da2-94be-fbea373e6e07
0198bedc-c95f-7ebd-95e3-85ab419da00a
0198bedc-c95f-7fd3-81d8-ff10a0075b6e
0198bedc-c960-70ee-87a7-b5a03c5d1ac6
0198bedc-c960-7209-9409-add2f19746d1
0198bedc-c960-7323-a63f-423a24ae5f0c
0198bedc-c960-743e-81e3-00596cbfd38c
0198bedc-c960-7559-a391-2996acb3f277
0198bedc-c960-766f-8fdc-2363759bc546

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)

1f07c71a-3fb8-6b18-8e9a-4cf95d479851
1f07c71a-3fb8-6cb2-8e9a-4cf95d479851
1f07c71a-3fb8-6d98-8e9a-4cf95d479851
1f07c71a-3fb8-6e74-8e9a-4cf95d479851
1f07c71a-3fb8-6f3c-8e9a-4cf95d479851
1f07c71a-3fb9-6004-8e9a-4cf95d479851
1f07c71a-3fb9-60cc-8e9a-4cf95d479851
1f07c71a-3fb9-618a-8e9a-4cf95d479851
1f07c71a-3fb9-6252-8e9a-4cf95d479851
1f07c71a-3fb9-6310-8e9a-4cf95d479851
1f07c71a-3fb9-6464-8e9a-4cf95d479851
1f07c71a-3fb9-652c-8e9a-4cf95d479851
1f07c71a-3fb9-65f4-8e9a-4cf95d479851
1f07c71a-3fb9-66b2-8e9a-4cf95d479851
1f07c71a-3fb9-6770-8e9a-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)

dcd58393-a897-4253-9c12-94936f78c780
6a964507-b575-4d7d-9b4f-0a895f363ddd
21f55c86-82d9-4a57-931e-4043c7e603d1
042bd586-2661-42db-8d16-762927efa0f2
483f7366-1cd9-4d2f-8eba-ab9eee1a49f1
b8226ea0-336a-47fe-9d14-457cfd0e249a
34295445-99ad-448e-bd98-7e3c843e27aa
6209e72d-3e26-40e8-95f5-2bb08efa3c16
f7786956-e889-4996-8102-745f82205e06
83ca56d1-e668-40d9-b322-e0b0d665f8b4
9cb64e9b-1cdd-4bcc-94fc-cba6b7734cc7
d358b79a-a893-41b1-a4c5-907dab478343
ed4411cf-6c0f-45f2-869e-54b4474cb71a
0e90b1d7-530e-4e21-a038-296be4472070
6f808370-c126-4e81-bf08-673c2cd10408

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)

a3fb9c84-7c71-11f0-8e9a-4cf95d479851
a3fb9ce8-7c71-11f0-8e9a-4cf95d479851
a3fb9d56-7c71-11f0-8e9a-4cf95d479851
a3fb9dba-7c71-11f0-8e9a-4cf95d479851
a3fb9e1e-7c71-11f0-8e9a-4cf95d479851
a3fb9e82-7c71-11f0-8e9a-4cf95d479851
a3fb9edc-7c71-11f0-8e9a-4cf95d479851
a3fb9f40-7c71-11f0-8e9a-4cf95d479851
a3fb9f9a-7c71-11f0-8e9a-4cf95d479851
a3fb9ffe-7c71-11f0-8e9a-4cf95d479851
a3fba062-7c71-11f0-8e9a-4cf95d479851
a3fba0c6-7c71-11f0-8e9a-4cf95d479851
a3fba134-7c71-11f0-8e9a-4cf95d479851
a3fba198-7c71-11f0-8e9a-4cf95d479851
a3fba1f2-7c71-11f0-8e9a-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)

4b5a4825-cb04-860e-87e9-5ce32bd83b97
41034925-cb04-860e-87e9-5ce32bd83b97
cecf4a25-cb04-860e-87e9-5ce32bd83b97
a7574b25-cb04-860e-87e9-5ce32bd83b97
a51d4c25-cb04-860e-87e9-5ce32bd83b97
52e44d25-cb04-860e-87e9-5ce32bd83b97
daab4e25-cb04-860e-87e9-5ce32bd83b97
a7994f25-cb04-860e-87e9-5ce32bd83b97
31495025-cb04-860e-87e9-5ce32bd83b97
d2e75125-cb04-860e-87e9-5ce32bd83b97
8ead5225-cb04-860e-87e9-5ce32bd83b97
82035325-cb04-860e-87e9-5ce32bd83b97
0be05425-cb04-860e-87e9-5ce32bd83b97
b0965525-cb04-860e-87e9-5ce32bd83b97
6a755625-cb04-860e-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: