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)

019c34cf-603c-76de-b24c-dc3bf3f0a8c7
019c34cf-603c-78d1-bf5c-3dfb5c5d987e
019c34cf-603c-7a5f-8871-c7e8f828ceb9
019c34cf-603c-7bbf-ae07-c073f1ec64a6
019c34cf-603c-7d1f-855c-acace2b10b51
019c34cf-603c-7e6b-b4d0-031a3fbca944
019c34cf-603c-7fb3-9f46-2dbc00466dfb
019c34cf-603d-7107-9184-d91ecf2ac7ce
019c34cf-603d-7252-8ccf-2ccc47f2796f
019c34cf-603d-739e-8f11-56d4193994e8
019c34cf-603d-74f6-903b-6bc8da994485
019c34cf-603d-763e-8efb-fcb26889aecd
019c34cf-603d-777d-bf31-1c1a5fe228da
019c34cf-603d-78bd-870e-fa197fd0c03e
019c34cf-603d-79f8-af05-0ed50799bd2d

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)

1f103a0f-820a-6b7c-8c52-4cf95d479851
1f103a0f-820a-6dac-8c52-4cf95d479851
1f103a0f-820a-6ef6-8c52-4cf95d479851
1f103a0f-820b-604a-8c52-4cf95d479851
1f103a0f-820b-6194-8c52-4cf95d479851
1f103a0f-820b-62c0-8c52-4cf95d479851
1f103a0f-820b-63ec-8c52-4cf95d479851
1f103a0f-820b-650e-8c52-4cf95d479851
1f103a0f-820b-663a-8c52-4cf95d479851
1f103a0f-820b-675c-8c52-4cf95d479851
1f103a0f-820b-690a-8c52-4cf95d479851
1f103a0f-820b-6a40-8c52-4cf95d479851
1f103a0f-820b-6b76-8c52-4cf95d479851
1f103a0f-820b-6cb6-8c52-4cf95d479851
1f103a0f-820b-6dd8-8c52-4cf95d479851

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)

74ede811-2a04-4abf-9067-d74e80e3a53f
760ba2cd-ad57-4f5e-8df5-ad4ccc0c2a7a
60886bf0-8f47-43c5-b38f-ee1e807374eb
8860576d-43bf-4136-bfdd-3e27d9fa47e5
71b92b37-e160-468b-aa1d-2f5d33ca0f2f
e31726f1-35bc-447b-9b26-c2a9b10eecf4
1065f131-bdf8-4aeb-accf-7f64e06b0f54
aad2fd1c-8192-4b9d-9cbd-51319a7f8398
f2e84de2-b1ea-4b1c-9ed8-22de9d9ca686
eb386bf1-af09-4c08-a449-e408127912cf
59263c93-b6fd-49de-b450-9735e8c57b41
1d599c66-0364-446c-995a-c11d9189df4f
dcd3a049-bd58-4d6a-a7ed-e5c16a525152
ae65a542-3937-4f99-8170-b96097ca1614
ed218eb4-f525-409e-954e-2ce11fcfe6af

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)

f820c486-03a0-11f1-8c52-4cf95d479851
f820c512-03a0-11f1-8c52-4cf95d479851
f820c5a8-03a0-11f1-8c52-4cf95d479851
f820c634-03a0-11f1-8c52-4cf95d479851
f820c6c0-03a0-11f1-8c52-4cf95d479851
f820c74c-03a0-11f1-8c52-4cf95d479851
f820c7ce-03a0-11f1-8c52-4cf95d479851
f820c850-03a0-11f1-8c52-4cf95d479851
f820c8d2-03a0-11f1-8c52-4cf95d479851
f820c954-03a0-11f1-8c52-4cf95d479851
f820c9cc-03a0-11f1-8c52-4cf95d479851
f820ca58-03a0-11f1-8c52-4cf95d479851
f820cad0-03a0-11f1-8c52-4cf95d479851
f820cb52-03a0-11f1-8c52-4cf95d479851
f820cbde-03a0-11f1-8c52-4cf95d479851

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)

daebc61f-fc04-8502-87ea-5ce32bd83b97
7954c71f-fc04-8502-87ea-5ce32bd83b97
343cc81f-fc04-8502-87ea-5ce32bd83b97
ed29c91f-fc04-8502-87ea-5ce32bd83b97
c22cca1f-fc04-8502-87ea-5ce32bd83b97
deddcb1f-fc04-8502-87ea-5ce32bd83b97
53dccc1f-fc04-8502-87ea-5ce32bd83b97
6ccdcd1f-fc04-8502-87ea-5ce32bd83b97
ef1ece1f-fc04-8502-87ea-5ce32bd83b97
4194cf1f-fc04-8502-87ea-5ce32bd83b97
3b86d01f-fc04-8502-87ea-5ce32bd83b97
3ea9d11f-fc04-8502-87ea-5ce32bd83b97
adb1d21f-fc04-8502-87ea-5ce32bd83b97
feb0d31f-fc04-8502-87ea-5ce32bd83b97
7b17d41f-fc04-8502-87ea-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: