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)

019bfc46-2319-7d9e-95a2-b7c9943e779b
019bfc46-2319-7f34-b159-a6cb15429c93
019bfc46-231a-7077-9ad4-043ee0b89245
019bfc46-231a-7196-9b50-b8ddb3eba6ed
019bfc46-231a-72b1-8d65-71173f7061dc
019bfc46-231a-73c7-aec1-c6d2ccd317dd
019bfc46-231a-74de-9f65-752f6973ae32
019bfc46-231a-75f4-9a5c-ea30649ca644
019bfc46-231a-77c3-acef-21dafb601482
019bfc46-231a-78e6-951a-d04af01bffaa
019bfc46-231a-7a9c-8fc2-65c208d7e144
019bfc46-231a-7bbb-ba4a-31d0001d3b13
019bfc46-231a-7cda-8555-d3bdf6f79fb5
019bfc46-231a-7df4-b19e-542081f0049e
019bfc46-231a-7f23-bbb2-b475b040067e

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)

1f0fb008-73c9-6072-80e9-4cf95d479851
1f0fb008-73c9-6220-80e9-4cf95d479851
1f0fb008-73c9-632e-80e9-4cf95d479851
1f0fb008-73c9-6400-80e9-4cf95d479851
1f0fb008-73c9-64c8-80e9-4cf95d479851
1f0fb008-73c9-6590-80e9-4cf95d479851
1f0fb008-73c9-6662-80e9-4cf95d479851
1f0fb008-73c9-6720-80e9-4cf95d479851
1f0fb008-73c9-67de-80e9-4cf95d479851
1f0fb008-73c9-689c-80e9-4cf95d479851
1f0fb008-73c9-69fa-80e9-4cf95d479851
1f0fb008-73c9-6ad6-80e9-4cf95d479851
1f0fb008-73c9-6b94-80e9-4cf95d479851
1f0fb008-73c9-6c52-80e9-4cf95d479851
1f0fb008-73c9-6d10-80e9-4cf95d479851

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)

edcde5eb-1d00-4796-b748-c749cb82ab24
de4ec0e0-6ee3-4bb4-899f-6a26d716bc5a
d236ccf9-e73a-4fc6-9c63-43a130298e74
168fcaaf-0b11-4153-b023-b677cc288208
bc26da4e-11eb-4c74-b00b-a18b80eb8db0
6bb35416-c7a2-4e0c-a52e-86d4be1b06df
f9bc6de1-bdca-4c27-b46c-8a63e72d9ac2
791990ad-1ecd-4943-99e7-80034a7068e7
8fb3e7a9-f734-4899-b912-e75d59188ad6
c17eb528-be6a-4762-adeb-f8e3b2d5a5d3
5e45d623-55b6-401b-8d78-c5b613153368
f40cb9c3-0546-4d11-864b-1d3cd2867e7f
247ffda2-bba3-4e3a-91f9-9e44360babb7
d29a9264-7d5f-4b8d-ab6d-8fb4376f1faf
cdd525ff-e1cf-401f-9e5e-e5b8ffac6655

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)

873ca22e-fb00-11f0-80e9-4cf95d479851
873ca29c-fb00-11f0-80e9-4cf95d479851
873ca300-fb00-11f0-80e9-4cf95d479851
873ca364-fb00-11f0-80e9-4cf95d479851
873ca3c8-fb00-11f0-80e9-4cf95d479851
873ca436-fb00-11f0-80e9-4cf95d479851
873ca49a-fb00-11f0-80e9-4cf95d479851
873ca508-fb00-11f0-80e9-4cf95d479851
873ca58a-fb00-11f0-80e9-4cf95d479851
873ca602-fb00-11f0-80e9-4cf95d479851
873ca666-fb00-11f0-80e9-4cf95d479851
873ca6d4-fb00-11f0-80e9-4cf95d479851
873ca72e-fb00-11f0-80e9-4cf95d479851
873ca792-fb00-11f0-80e9-4cf95d479851
873ca7f6-fb00-11f0-80e9-4cf95d479851

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)

72969835-1b05-8a01-87ea-5ce32bd83b97
06289935-1b05-8a01-87ea-5ce32bd83b97
074b9a35-1b05-8a01-87ea-5ce32bd83b97
80d19b35-1b05-8a01-87ea-5ce32bd83b97
32519c35-1b05-8a01-87ea-5ce32bd83b97
52d49d35-1b05-8a01-87ea-5ce32bd83b97
21219e35-1b05-8a01-87ea-5ce32bd83b97
22259f35-1b05-8a01-87ea-5ce32bd83b97
5f4aa035-1b05-8a01-87ea-5ce32bd83b97
32eea135-1b05-8a01-87ea-5ce32bd83b97
a820a235-1b05-8a01-87ea-5ce32bd83b97
7ad8a335-1b05-8a01-87ea-5ce32bd83b97
ae67a435-1b05-8a01-87ea-5ce32bd83b97
2fbaa535-1b05-8a01-87ea-5ce32bd83b97
a843a635-1b05-8a01-87ea-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: