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)

019df9b0-6e17-7efa-8931-f5629efc993a
019df9b0-6e18-707f-b436-c3a0e89b997b
019df9b0-6e18-71bb-8fc3-c93919a3a379
019df9b0-6e18-72d5-a7d6-ed5dca332aeb
019df9b0-6e18-73e8-863f-d653f0a73442
019df9b0-6e18-74fa-8876-99ef0cc963f9
019df9b0-6e18-760d-b8c7-62ac9ac4df03
019df9b0-6e18-771b-8b75-97ca14495c9f
019df9b0-6e18-782e-9066-c420c7a92011
019df9b0-6e18-7940-af3e-73113745d4a2
019df9b0-6e18-7a52-a52b-caad2c75759a
019df9b0-6e18-7b65-8a42-8dec4d2b1ca8
019df9b0-6e18-7c77-8b3d-cdc5b997ac74
019df9b0-6e18-7d86-a90a-9f36038653ea
019df9b0-6e18-7e98-9163-e60b59ff6fe5

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)

1f148bb8-f4df-60cc-afe7-4cf95d479851
1f148bb8-f4df-6266-afe7-4cf95d479851
1f148bb8-f4df-634c-afe7-4cf95d479851
1f148bb8-f4df-641e-afe7-4cf95d479851
1f148bb8-f4df-64e6-afe7-4cf95d479851
1f148bb8-f4df-65ae-afe7-4cf95d479851
1f148bb8-f4df-6676-afe7-4cf95d479851
1f148bb8-f4df-673e-afe7-4cf95d479851
1f148bb8-f4df-6810-afe7-4cf95d479851
1f148bb8-f4df-68d8-afe7-4cf95d479851
1f148bb8-f4df-6a68-afe7-4cf95d479851
1f148bb8-f4df-6bbc-afe7-4cf95d479851
1f148bb8-f4df-6c98-afe7-4cf95d479851
1f148bb8-f4df-6d6a-afe7-4cf95d479851
1f148bb8-f4df-6e32-afe7-4cf95d479851

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)

7bf06488-465d-4af8-8768-46311e39a2dd
2fbacca3-5ae2-4b45-b8fc-2545b3552f9b
63572e93-eb9d-42ac-a641-7f23ab080246
96f943fb-f4b9-453c-a28c-5d5d8de3ea31
2061538b-70c2-446c-80f6-c1b7a6248ce0
4856e685-be06-49db-b7bf-34d7818adcb5
bf3c841f-030a-4a24-b680-674aa309b83b
66f29175-a895-4577-a742-8fc7e7c16618
1237b206-8006-4d0c-bd54-e6e54a9bf40b
d2cf65e6-dd3f-4d61-905d-5a6cd0f727c8
e14e4e52-5982-4be4-a1d8-72831da21cdf
8304b3fc-33ef-409b-addd-cfdccba86217
c93b4ea3-69c0-49bc-9cf0-d42284286e7a
ba7b08a2-f15f-4e57-9b80-2856b3f43ba8
f4bb37f6-b395-4fcc-9a1a-5fcc6253ae26

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)

8f4e0364-48bb-11f1-afe7-4cf95d479851
8f4e03c8-48bb-11f1-afe7-4cf95d479851
8f4e0436-48bb-11f1-afe7-4cf95d479851
8f4e049a-48bb-11f1-afe7-4cf95d479851
8f4e0508-48bb-11f1-afe7-4cf95d479851
8f4e0562-48bb-11f1-afe7-4cf95d479851
8f4e05c6-48bb-11f1-afe7-4cf95d479851
8f4e062a-48bb-11f1-afe7-4cf95d479851
8f4e068e-48bb-11f1-afe7-4cf95d479851
8f4e06f2-48bb-11f1-afe7-4cf95d479851
8f4e0756-48bb-11f1-afe7-4cf95d479851
8f4e07ba-48bb-11f1-afe7-4cf95d479851
8f4e081e-48bb-11f1-afe7-4cf95d479851
8f4e0878-48bb-11f1-afe7-4cf95d479851
8f4e08dc-48bb-11f1-afe7-4cf95d479851

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)

20068d2a-a604-8d07-87ea-5ce32bd83b97
37068e2a-a604-8d07-87ea-5ce32bd83b97
0e5f8f2a-a604-8d07-87ea-5ce32bd83b97
43fc902a-a604-8d07-87ea-5ce32bd83b97
2e87912a-a604-8d07-87ea-5ce32bd83b97
9cb1932a-a604-8d07-87ea-5ce32bd83b97
1474942a-a604-8d07-87ea-5ce32bd83b97
e2b5952a-a604-8d07-87ea-5ce32bd83b97
ee9f962a-a604-8d07-87ea-5ce32bd83b97
9415972a-a604-8d07-87ea-5ce32bd83b97
e93c982a-a604-8d07-87ea-5ce32bd83b97
450e992a-a604-8d07-87ea-5ce32bd83b97
98e99a2a-a604-8d07-87ea-5ce32bd83b97
438c9b2a-a604-8d07-87ea-5ce32bd83b97
f0759c2a-a604-8d07-87ea-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: