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)

01a139ce-9b91-7ff4-bbea-9b90f27d20cf
01a139ce-9b92-719e-bc49-6816ef8e994c
01a139ce-9b92-72de-8403-566ae05b0355
01a139ce-9b92-73fc-8c32-f4271a0204c2
01a139ce-9b92-7517-aef5-15e6dd47673c
01a139ce-9b92-7632-b287-a04998824ccd
01a139ce-9b92-7748-a2be-cbc6ed9dfbba
01a139ce-9b92-785f-98ec-7ea4df001b1f
01a139ce-9b92-7975-a70b-e57e420db1ae
01a139ce-9b92-7a8c-bc60-9157ab8f6a86
01a139ce-9b92-7ba2-b6a8-0e26b37a945e
01a139ce-9b92-7cb9-96cd-61073d863570
01a139ce-9b92-7dd8-945e-08a7934f6fbd
01a139ce-9b92-7ef2-ba35-08f601e6229d
01a139ce-9b93-7009-884c-cabef944ebf2

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)

1f1c7b42-a1e6-6222-96d4-4cf95d479851
1f1c7b42-a1e6-63da-96d4-4cf95d479851
1f1c7b42-a1e6-64c0-96d4-4cf95d479851
1f1c7b42-a1e6-6588-96d4-4cf95d479851
1f1c7b42-a1e6-6650-96d4-4cf95d479851
1f1c7b42-a1e6-670e-96d4-4cf95d479851
1f1c7b42-a1e6-67cc-96d4-4cf95d479851
1f1c7b42-a1e6-688a-96d4-4cf95d479851
1f1c7b42-a1e6-6948-96d4-4cf95d479851
1f1c7b42-a1e6-6a06-96d4-4cf95d479851
1f1c7b42-a1e6-6b3c-96d4-4cf95d479851
1f1c7b42-a1e6-6c04-96d4-4cf95d479851
1f1c7b42-a1e6-6cc2-96d4-4cf95d479851
1f1c7b42-a1e6-6d76-96d4-4cf95d479851
1f1c7b42-a1e6-6e34-96d4-4cf95d479851

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)

2a1e6f06-c7b4-11f1-96d4-4cf95d479851
2a1e6f6a-c7b4-11f1-96d4-4cf95d479851
2a1e6fce-c7b4-11f1-96d4-4cf95d479851
2a1e7032-c7b4-11f1-96d4-4cf95d479851
2a1e708c-c7b4-11f1-96d4-4cf95d479851
2a1e70f0-c7b4-11f1-96d4-4cf95d479851
2a1e7154-c7b4-11f1-96d4-4cf95d479851
2a1e71b8-c7b4-11f1-96d4-4cf95d479851
2a1e721c-c7b4-11f1-96d4-4cf95d479851
2a1e7276-c7b4-11f1-96d4-4cf95d479851
2a1e72e4-c7b4-11f1-96d4-4cf95d479851
2a1e7348-c7b4-11f1-96d4-4cf95d479851
2a1e73a2-c7b4-11f1-96d4-4cf95d479851
2a1e73fc-c7b4-11f1-96d4-4cf95d479851
2a1e7460-c7b4-11f1-96d4-4cf95d479851

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)

026bfc2b-4b02-8f11-87ea-5ce32bd83b97
b800fd2b-4b02-8f11-87ea-5ce32bd83b97
3cbefe2b-4b02-8f11-87ea-5ce32bd83b97
1d39ff2b-4b02-8f11-87ea-5ce32bd83b97
0272012c-4b02-8f11-87ea-5ce32bd83b97
6e32022c-4b02-8f11-87ea-5ce32bd83b97
255f032c-4b02-8f11-87ea-5ce32bd83b97
6566042c-4b02-8f11-87ea-5ce32bd83b97
d170052c-4b02-8f11-87ea-5ce32bd83b97
66b7062c-4b02-8f11-87ea-5ce32bd83b97
1105072c-4b02-8f11-87ea-5ce32bd83b97
b8a2082c-4b02-8f11-87ea-5ce32bd83b97
f3ba092c-4b02-8f11-87ea-5ce32bd83b97
ba1c0a2c-4b02-8f11-87ea-5ce32bd83b97
26c80b2c-4b02-8f11-87ea-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)

afcb5901-058d-49a1-9f4b-c1fbb3602123
503f7f49-6218-44ef-8a61-5427f51d8008
e1c7307e-a149-44ed-8057-cc83d0c4e6fd
cbc0e226-365e-4ef3-be37-d4761bd43cd5
4640bf90-195c-4eb6-8fcc-acdbf676f371
e2d92202-a32d-4512-8b85-75475a9777a4
4552c665-606d-431a-8e31-7c808e84ffd7
b831404f-ca83-4fb3-9bee-32b17466debd
4fbcc80e-08bb-4b3d-a9fe-9c2aff027df4
598c6258-cfc8-4d3d-a810-b2569b562d93
f5f0799b-7877-404d-9f19-d42611a1fab0
fa80dfd1-f38a-46ec-9aed-d9c7114169d8
7abbf0ba-ff53-4366-8433-bd2de475a94e
8ee9e195-c115-42ba-9ce1-292c9751c35a
4d80d0d7-0fe9-495b-a4cd-87883e2b84ee

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: