UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

01a0481d-e443-73c3-8626-b1f6a7e708db
01a0481d-e443-7582-bb3d-bb12535574d8
01a0481d-e443-76c1-9cba-721caea60476
01a0481d-e443-77e0-bf92-2e935830f959
01a0481d-e443-78fe-96ca-fe227f5af408
01a0481d-e443-7a15-b8f7-5919e254ce0f
01a0481d-e443-7b2c-aed4-5ae68057baae
01a0481d-e443-7c3e-a013-27fbade49b6e
01a0481d-e443-7d50-81a6-c7e19308fabd
01a0481d-e443-7e63-abe7-a0f7e9e80ce3
01a0481d-e443-7f79-881d-ebe2b8594e6f
01a0481d-e444-7090-a329-b23cd99926ff
01a0481d-e444-71a6-9e3b-ee1fba74875e
01a0481d-e444-72bd-a94e-9a1557fcb796
01a0481d-e444-73cf-bdc5-ad597495d508

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)

1f1a2d32-325e-6f40-8d72-4cf95d479851
1f1a2d32-325f-60e4-8d72-4cf95d479851
1f1a2d32-325f-61d4-8d72-4cf95d479851
1f1a2d32-325f-62b0-8d72-4cf95d479851
1f1a2d32-325f-638c-8d72-4cf95d479851
1f1a2d32-325f-645e-8d72-4cf95d479851
1f1a2d32-325f-6526-8d72-4cf95d479851
1f1a2d32-325f-65f8-8d72-4cf95d479851
1f1a2d32-325f-66d4-8d72-4cf95d479851
1f1a2d32-325f-679c-8d72-4cf95d479851
1f1a2d32-325f-68fa-8d72-4cf95d479851
1f1a2d32-325f-69d6-8d72-4cf95d479851
1f1a2d32-325f-6a9e-8d72-4cf95d479851
1f1a2d32-325f-6b5c-8d72-4cf95d479851
1f1a2d32-325f-6c24-8d72-4cf95d479851

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)

2325fd00-a2d3-11f1-8d72-4cf95d479851
2325fd78-a2d3-11f1-8d72-4cf95d479851
2325fddc-a2d3-11f1-8d72-4cf95d479851
2325fe4a-a2d3-11f1-8d72-4cf95d479851
2325feae-a2d3-11f1-8d72-4cf95d479851
2325ff1c-a2d3-11f1-8d72-4cf95d479851
2325ff80-a2d3-11f1-8d72-4cf95d479851
23260002-a2d3-11f1-8d72-4cf95d479851
23260066-a2d3-11f1-8d72-4cf95d479851
232600d4-a2d3-11f1-8d72-4cf95d479851
23260138-a2d3-11f1-8d72-4cf95d479851
2326019c-a2d3-11f1-8d72-4cf95d479851
2326020a-a2d3-11f1-8d72-4cf95d479851
2326026e-a2d3-11f1-8d72-4cf95d479851
232602d2-a2d3-11f1-8d72-4cf95d479851

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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

1d07ab0d-ae02-800f-87ea-5ce32bd83b97
11cbac0d-ae02-800f-87ea-5ce32bd83b97
9013ad0d-ae02-800f-87ea-5ce32bd83b97
0278ae0d-ae02-800f-87ea-5ce32bd83b97
9fc0af0d-ae02-800f-87ea-5ce32bd83b97
b6e8b00d-ae02-800f-87ea-5ce32bd83b97
0172b10d-ae02-800f-87ea-5ce32bd83b97
9e5eb20d-ae02-800f-87ea-5ce32bd83b97
5c9bb30d-ae02-800f-87ea-5ce32bd83b97
1143b40d-ae02-800f-87ea-5ce32bd83b97
e75db50d-ae02-800f-87ea-5ce32bd83b97
c23cb60d-ae02-800f-87ea-5ce32bd83b97
f2dab70d-ae02-800f-87ea-5ce32bd83b97
5d83b80d-ae02-800f-87ea-5ce32bd83b97
6242b90d-ae02-800f-87ea-5ce32bd83b97

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)

98e84bde-2bab-46ad-b204-9a0b13b0779f
accef873-ba17-4524-9379-6b45d9994cbf
641c8571-129b-41c8-b771-f97b0f579678
a78e7a96-42df-40f6-9db1-f7d5096c3025
30a466bc-61bd-440d-ae31-b95d1d429871
ce4f0a21-f7e4-4b35-b145-5de177a08610
d6b2dc3d-3c7e-42ab-bc16-7f5acac7e3df
bebe8a6d-04af-4d91-ba5c-b63e1df31e98
eb02223d-50e2-413c-ab3a-c87efe96a78f
7fcf7ad3-dc20-4413-befa-95477651204a
d5737618-c80e-45c1-a803-a08fbd238895
7f36edf8-93cb-4791-a6de-a7dfb426bba2
45571191-2016-4a67-9256-30ece0ed1504
90dac099-53b3-42a1-8b62-da34e715d5d3
1c46f29d-533d-4f80-a7fe-adb5216676fb

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: