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)

01a16e53-21ab-79a6-bd3e-c6f0e6d568e1
01a16e53-21ab-7b27-92fb-1238be70d5af
01a16e53-21ab-7c63-a409-927c037ac627
01a16e53-21ab-7d7d-ace6-ff284230209d
01a16e53-21ab-7e98-ad2e-eb1bffe12f60
01a16e53-21ab-7faf-b075-924953ad29a6
01a16e53-21ac-70c5-973d-ad6eaae2d2eb
01a16e53-21ac-71dc-8fc5-cb89d322b087
01a16e53-21ac-72ee-9a6e-06dc77e35b31
01a16e53-21ac-7405-a44e-5975b6e407d0
01a16e53-21ac-751f-89b3-d4118b7a9bb5
01a16e53-21ac-7642-a8ba-d4987254857b
01a16e53-21ac-7759-915b-ac7b08a54545
01a16e53-21ac-786b-931a-585230834700
01a16e53-21ac-797d-a0e5-29c9e5d03d69

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)

1f1cfb7a-2d4a-69dc-9d53-4cf95d479851
1f1cfb7a-2d4a-6b8a-9d53-4cf95d479851
1f1cfb7a-2d4a-6c70-9d53-4cf95d479851
1f1cfb7a-2d4a-6d42-9d53-4cf95d479851
1f1cfb7a-2d4a-6e14-9d53-4cf95d479851
1f1cfb7a-2d4a-6edc-9d53-4cf95d479851
1f1cfb7a-2d4a-6fae-9d53-4cf95d479851
1f1cfb7a-2d4b-6076-9d53-4cf95d479851
1f1cfb7a-2d4b-6134-9d53-4cf95d479851
1f1cfb7a-2d4b-61fc-9d53-4cf95d479851
1f1cfb7a-2d4b-6350-9d53-4cf95d479851
1f1cfb7a-2d4b-6418-9d53-4cf95d479851
1f1cfb7a-2d4b-64e0-9d53-4cf95d479851
1f1cfb7a-2d4b-65b2-9d53-4cf95d479851
1f1cfb7a-2d4b-6670-9d53-4cf95d479851

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)

a2d4b74c-cfb7-11f1-9d53-4cf95d479851
a2d4b7b0-cfb7-11f1-9d53-4cf95d479851
a2d4b814-cfb7-11f1-9d53-4cf95d479851
a2d4b878-cfb7-11f1-9d53-4cf95d479851
a2d4b8e6-cfb7-11f1-9d53-4cf95d479851
a2d4b94a-cfb7-11f1-9d53-4cf95d479851
a2d4b9ae-cfb7-11f1-9d53-4cf95d479851
a2d4ba1c-cfb7-11f1-9d53-4cf95d479851
a2d4ba80-cfb7-11f1-9d53-4cf95d479851
a2d4bae4-cfb7-11f1-9d53-4cf95d479851
a2d4bb3e-cfb7-11f1-9d53-4cf95d479851
a2d4bb98-cfb7-11f1-9d53-4cf95d479851
a2d4bbfc-cfb7-11f1-9d53-4cf95d479851
a2d4bc56-cfb7-11f1-9d53-4cf95d479851
a2d4bcba-cfb7-11f1-9d53-4cf95d479851

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)

068c4d2c-6803-8912-87ea-5ce32bd83b97
4df24e2c-6803-8912-87ea-5ce32bd83b97
00574f2c-6803-8912-87ea-5ce32bd83b97
8f3d502c-6803-8912-87ea-5ce32bd83b97
ced4512c-6803-8912-87ea-5ce32bd83b97
6aaa522c-6803-8912-87ea-5ce32bd83b97
732c532c-6803-8912-87ea-5ce32bd83b97
2eec542c-6803-8912-87ea-5ce32bd83b97
7863552c-6803-8912-87ea-5ce32bd83b97
0863562c-6803-8912-87ea-5ce32bd83b97
8318572c-6803-8912-87ea-5ce32bd83b97
3b98582c-6803-8912-87ea-5ce32bd83b97
1f4c592c-6803-8912-87ea-5ce32bd83b97
deda5a2c-6803-8912-87ea-5ce32bd83b97
bd7c5b2c-6803-8912-87ea-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)

ef41003e-3d20-4d31-baf0-927e48a36372
e50f3b9a-5422-4ab8-a450-c388a618c87f
085680d0-b0af-4b61-81ea-87f597d8aeb1
5dfcd232-3494-4e13-86f6-54089f7cf786
ad933d55-6356-4ef1-b242-74bf945ff305
ccf54c3b-c1e6-46da-93c8-b0c5d27791dd
69de5343-7d96-41b1-992c-d9578ce6a251
cf694928-60c4-4c67-bb30-ddf07c39c07c
d120349d-3918-4512-826c-710a5ab3f5e4
5dab4486-88a3-4cd3-ad0f-52559c10d14b
17bf1f75-555b-44f6-92cb-3ba24917ba23
a86e3e7e-828d-43cb-ae88-189e29863083
35bb3715-a7da-434a-a1e4-a11e11149ab9
0b963a21-1b4d-4b9f-9a7f-cd769db01646
53ca827c-1b78-413e-aa61-6e7bf08dd9ee

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: