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)

019d9554-3638-7b61-83ba-e28249eabc07
019d9554-3638-7cea-b35f-35ffdcd6ca92
019d9554-3638-7e25-bb57-0b23352c69ce
019d9554-3638-7f48-8bb0-e260754da5d9
019d9554-3639-7063-aa8a-eee891484d8e
019d9554-3639-7179-a4d2-ac1250cd52c5
019d9554-3639-7290-932d-20ecb8fec4f3
019d9554-3639-73a6-a794-28dc53956f0f
019d9554-3639-74c1-83e7-7255b408ec6b
019d9554-3639-75d8-90aa-2ee0a013190e
019d9554-3639-76ee-b2a5-bb22d02d516d
019d9554-3639-7805-b04c-0c4ca7246fcc
019d9554-3639-791b-a332-9f1a9245e732
019d9554-3639-7a32-b26c-8f10aa7fceb0
019d9554-3639-7b48-9368-4c35255f8c48

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)

1f1396b3-d077-61e4-9c55-4cf95d479851
1f1396b3-d077-6360-9c55-4cf95d479851
1f1396b3-d077-6446-9c55-4cf95d479851
1f1396b3-d077-650e-9c55-4cf95d479851
1f1396b3-d077-65d6-9c55-4cf95d479851
1f1396b3-d077-6694-9c55-4cf95d479851
1f1396b3-d077-6752-9c55-4cf95d479851
1f1396b3-d077-6810-9c55-4cf95d479851
1f1396b3-d077-68c4-9c55-4cf95d479851
1f1396b3-d077-698c-9c55-4cf95d479851
1f1396b3-d077-6ab8-9c55-4cf95d479851
1f1396b3-d077-6b8a-9c55-4cf95d479851
1f1396b3-d077-6c3e-9c55-4cf95d479851
1f1396b3-d077-6d10-9c55-4cf95d479851
1f1396b3-d077-6dce-9c55-4cf95d479851

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)

c72caa57-7832-4f4b-a389-4b654eaca864
f482c990-1d6c-4c07-8770-54896f6ad957
90ceeac4-545a-4b3c-8dca-8bf80b7232c2
86af89b8-9f2a-4abb-b236-4233e7b814e3
86d5efd4-347b-4e72-8c1c-a06e5fc6638a
1497dcd8-0020-4348-9354-917d12a2a568
059be283-f391-4005-98db-20e3fc5df40d
9f1600b6-e217-4b30-929d-b9475fc9f624
dc74156c-8ff2-4899-acf8-08d037aa6f61
6c339bbc-5f9f-4ea8-9fd4-84569f25ee99
176b7ec1-6c53-4e63-b676-d08745269af8
8a5cdc42-c5d4-4149-a611-96144db9b8d7
7b8aa6ab-6bb6-41a6-9321-c2f1d7f03688
f17d3cdc-eca2-43a1-9c15-f1635b84dca2
ff00c52c-b33a-41d7-bc5c-2d195de3a491

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)

3d07835a-396b-11f1-9c55-4cf95d479851
3d0783c8-396b-11f1-9c55-4cf95d479851
3d07842c-396b-11f1-9c55-4cf95d479851
3d07849a-396b-11f1-9c55-4cf95d479851
3d0784fe-396b-11f1-9c55-4cf95d479851
3d078562-396b-11f1-9c55-4cf95d479851
3d0785c6-396b-11f1-9c55-4cf95d479851
3d07862a-396b-11f1-9c55-4cf95d479851
3d07868e-396b-11f1-9c55-4cf95d479851
3d0786f2-396b-11f1-9c55-4cf95d479851
3d078760-396b-11f1-9c55-4cf95d479851
3d0787ce-396b-11f1-9c55-4cf95d479851
3d07883c-396b-11f1-9c55-4cf95d479851
3d0788aa-396b-11f1-9c55-4cf95d479851
3d078904-396b-11f1-9c55-4cf95d479851

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)

d8ad5639-e701-8a06-87ea-5ce32bd83b97
034d5739-e701-8a06-87ea-5ce32bd83b97
29cb5839-e701-8a06-87ea-5ce32bd83b97
49c65939-e701-8a06-87ea-5ce32bd83b97
d55e5a39-e701-8a06-87ea-5ce32bd83b97
c5c65b39-e701-8a06-87ea-5ce32bd83b97
e3e25d39-e701-8a06-87ea-5ce32bd83b97
b7b65e39-e701-8a06-87ea-5ce32bd83b97
e65e5f39-e701-8a06-87ea-5ce32bd83b97
55d96039-e701-8a06-87ea-5ce32bd83b97
43416139-e701-8a06-87ea-5ce32bd83b97
d7fa6239-e701-8a06-87ea-5ce32bd83b97
947d6339-e701-8a06-87ea-5ce32bd83b97
765e6439-e701-8a06-87ea-5ce32bd83b97
655b6539-e701-8a06-87ea-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: