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)

019cb298-a49f-7eda-a556-d70ebe7a8559
019cb298-a4a0-7161-9bb0-9e974144a6c8
019cb298-a4a0-72f2-b71d-2f9a6f4700cc
019cb298-a4a0-7452-8c7a-fa9c0becfaa8
019cb298-a4a0-75a6-a98a-8517da384d15
019cb298-a4a0-76fe-9442-d430011cc4cf
019cb298-a4a0-7852-9678-958ac66052d3
019cb298-a4a0-79aa-b132-472639d9134e
019cb298-a4a0-7afe-9a43-81063c819174
019cb298-a4a0-7c4e-a9ce-465b03e133cf
019cb298-a4a0-7da2-8418-d18473dcce35
019cb298-a4a0-7efa-b50b-d79a8de1b325
019cb298-a4a1-7052-a3da-1f9d9d7e40c6
019cb298-a4a1-71b7-a3d4-2cf31e84f086
019cb298-a4a1-730b-a52a-062374b4561f

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)

1f116d27-e201-6dc2-a6c6-4cf95d479851
1f116d27-e202-6060-a6c6-4cf95d479851
1f116d27-e202-61fa-a6c6-4cf95d479851
1f116d27-e202-6362-a6c6-4cf95d479851
1f116d27-e202-64d4-a6c6-4cf95d479851
1f116d27-e202-6628-a6c6-4cf95d479851
1f116d27-e202-670e-a6c6-4cf95d479851
1f116d27-e202-67cc-a6c6-4cf95d479851
1f116d27-e202-6894-a6c6-4cf95d479851
1f116d27-e202-6952-a6c6-4cf95d479851
1f116d27-e202-6a92-a6c6-4cf95d479851
1f116d27-e202-6b5a-a6c6-4cf95d479851
1f116d27-e202-6c18-a6c6-4cf95d479851
1f116d27-e202-6cd6-a6c6-4cf95d479851
1f116d27-e202-6e34-a6c6-4cf95d479851

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)

c367815f-0abc-48f9-8074-ffa05726dc77
7ac92be7-1035-4988-b1b2-514cfa5d5f4c
e32b5ec0-1bbc-4234-9ae7-1b3e3e47a71b
a187aaf3-a957-4218-827e-165831101923
2b20f517-1cd6-416f-a62d-eb7a511b6dda
39a8d4e8-a90d-43eb-acee-028441c72e51
335e41c7-6f49-43ba-bb95-342b6b9c1f49
ca7bf188-9051-4d9d-aeae-64389a2aeb6d
d694cc0e-2128-4e47-9dbb-2b83fc5b5981
535141df-e04f-415d-ae09-6e48e667092a
0e11d5e0-f6f4-496a-a886-c63bbe19249f
b2739140-e3ef-4232-95ec-f60c34174b20
d40d7587-2b2d-4341-b0d2-bf8282e5ed38
ceb8d305-22cc-47f8-9419-e02c62d9dacf
0fa1a8f3-3ce3-4146-a8fa-89af9e3d5d90

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)

7e2033a2-16d2-11f1-a6c6-4cf95d479851
7e203410-16d2-11f1-a6c6-4cf95d479851
7e203474-16d2-11f1-a6c6-4cf95d479851
7e2034e2-16d2-11f1-a6c6-4cf95d479851
7e20353c-16d2-11f1-a6c6-4cf95d479851
7e2035a0-16d2-11f1-a6c6-4cf95d479851
7e203604-16d2-11f1-a6c6-4cf95d479851
7e203672-16d2-11f1-a6c6-4cf95d479851
7e2036d6-16d2-11f1-a6c6-4cf95d479851
7e20374e-16d2-11f1-a6c6-4cf95d479851
7e2037a8-16d2-11f1-a6c6-4cf95d479851
7e20380c-16d2-11f1-a6c6-4cf95d479851
7e203870-16d2-11f1-a6c6-4cf95d479851
7e2038ca-16d2-11f1-a6c6-4cf95d479851
7e20392e-16d2-11f1-a6c6-4cf95d479851

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)

76530536-c001-8e03-87ea-5ce32bd83b97
03510636-c001-8e03-87ea-5ce32bd83b97
d72a0736-c001-8e03-87ea-5ce32bd83b97
38180836-c001-8e03-87ea-5ce32bd83b97
3bbb0936-c001-8e03-87ea-5ce32bd83b97
3eae0a36-c001-8e03-87ea-5ce32bd83b97
ec400b36-c001-8e03-87ea-5ce32bd83b97
a1fe0c36-c001-8e03-87ea-5ce32bd83b97
4cc60d36-c001-8e03-87ea-5ce32bd83b97
62a80e36-c001-8e03-87ea-5ce32bd83b97
c5120f36-c001-8e03-87ea-5ce32bd83b97
c5ff1036-c001-8e03-87ea-5ce32bd83b97
a3111136-c001-8e03-87ea-5ce32bd83b97
f5111236-c001-8e03-87ea-5ce32bd83b97
7e901336-c001-8e03-87ea-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: