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)

019bbb89-2b83-71c3-980a-5fd82fe36961
019bbb89-2b83-7359-bdf5-ff013d24935e
019bbb89-2b83-7498-96ba-b955e24ca3c1
019bbb89-2b83-75b7-b77d-a2dd8ad80cbe
019bbb89-2b83-76d5-889b-ef1c3b8ea9a0
019bbb89-2b83-77f0-a184-381a36fb5679
019bbb89-2b83-790f-a4af-8ec4cb93ec78
019bbb89-2b83-7a29-a028-123b98d511d4
019bbb89-2b83-7b40-81ef-0ed3569a53b9
019bbb89-2b83-7c5b-9a1b-9e50f60f2193
019bbb89-2b83-7d75-8680-b3c2ae3990fe
019bbb89-2b83-7e90-9395-1261b56c835a
019bbb89-2b83-7faa-a3d1-f139c96c2879
019bbb89-2b84-70c5-941b-c0845969577d
019bbb89-2b84-71e0-ae2d-0203f207e36d

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)

1f0f11fb-1b51-6ca6-b747-4cf95d479851
1f0f11fb-1b51-6e36-b747-4cf95d479851
1f0f11fb-1b51-6f1c-b747-4cf95d479851
1f0f11fb-1b51-6fee-b747-4cf95d479851
1f0f11fb-1b52-60b6-b747-4cf95d479851
1f0f11fb-1b52-6192-b747-4cf95d479851
1f0f11fb-1b52-625a-b747-4cf95d479851
1f0f11fb-1b52-6322-b747-4cf95d479851
1f0f11fb-1b52-63f4-b747-4cf95d479851
1f0f11fb-1b52-64bc-b747-4cf95d479851
1f0f11fb-1b52-65fc-b747-4cf95d479851
1f0f11fb-1b52-66d8-b747-4cf95d479851
1f0f11fb-1b52-6796-b747-4cf95d479851
1f0f11fb-1b52-685e-b747-4cf95d479851
1f0f11fb-1b52-691c-b747-4cf95d479851

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)

04ddd810-ec45-42fa-864d-1a09991019e7
a20d6bc5-3e4e-4d02-88a4-510bed068c88
d4175621-d3ad-4ac8-bf08-9e6be270f229
f65cdd3b-e010-415e-b58f-c23f58b66c4d
dd96e883-dc68-405f-8d0f-1aca2b1fe834
8348b087-53d6-42e9-8739-883954b22eb5
04f5c92f-27fc-4b9c-98a1-5599a1fc3baa
db419050-a68a-407d-b0db-e675354ce43b
8704baac-5011-4433-8c8c-4323922b4eba
01a91240-3a23-4f50-8328-2febc1342a8b
f7ed32e8-9306-45f4-bd46-86c3d3aed3b3
f15eb5fd-443a-43d0-be8c-ec7dae7502a4
17e89d75-ff98-453c-baaf-9ac8e5e388a1
58baeb47-591d-4c71-a215-d5f00640d4e8
d632e785-128b-4e74-a889-3027d2e5028f

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)

b1b52eda-f11f-11f0-b747-4cf95d479851
b1b52f48-f11f-11f0-b747-4cf95d479851
b1b52fac-f11f-11f0-b747-4cf95d479851
b1b5301a-f11f-11f0-b747-4cf95d479851
b1b53088-f11f-11f0-b747-4cf95d479851
b1b53100-f11f-11f0-b747-4cf95d479851
b1b53164-f11f-11f0-b747-4cf95d479851
b1b531c8-f11f-11f0-b747-4cf95d479851
b1b53236-f11f-11f0-b747-4cf95d479851
b1b5329a-f11f-11f0-b747-4cf95d479851
b1b532fe-f11f-11f0-b747-4cf95d479851
b1b5336c-f11f-11f0-b747-4cf95d479851
b1b533d0-f11f-11f0-b747-4cf95d479851
b1b53434-f11f-11f0-b747-4cf95d479851
b1b53498-f11f-11f0-b747-4cf95d479851

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)

4efa9e2f-e501-8e00-87ea-5ce32bd83b97
4e2ba02f-e501-8e00-87ea-5ce32bd83b97
15f8a12f-e501-8e00-87ea-5ce32bd83b97
423ca22f-e501-8e00-87ea-5ce32bd83b97
19cfa32f-e501-8e00-87ea-5ce32bd83b97
a2e6a42f-e501-8e00-87ea-5ce32bd83b97
560fa52f-e501-8e00-87ea-5ce32bd83b97
21d0a62f-e501-8e00-87ea-5ce32bd83b97
d6c0a72f-e501-8e00-87ea-5ce32bd83b97
cd82a82f-e501-8e00-87ea-5ce32bd83b97
0a33a92f-e501-8e00-87ea-5ce32bd83b97
d8acaa2f-e501-8e00-87ea-5ce32bd83b97
d8ceab2f-e501-8e00-87ea-5ce32bd83b97
881aac2f-e501-8e00-87ea-5ce32bd83b97
c1c7ad2f-e501-8e00-87ea-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: