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)

019f4bd9-2004-7042-85f0-e8cbeef5c2a6
019f4bd9-2005-71c7-9340-b8370ccf704b
019f4bd9-2005-72fe-9495-c63bed6e1506
019f4bd9-2005-7419-be7f-93c2d03ab5bd
019f4bd9-2005-752c-b256-b16e18fe5af6
019f4bd9-2005-7646-8c51-975a04479467
019f4bd9-2005-7759-a17a-ec6d7aafc8d2
019f4bd9-2005-786f-a40f-d2c7d84155f5
019f4bd9-2005-7982-a964-3a0c0b12bb00
019f4bd9-2005-7a94-b357-0283a2f67780
019f4bd9-2005-7ba6-aefa-df6a4c25ca90
019f4bd9-2005-7cb9-933a-ea959be726ef
019f4bd9-2005-7dcf-9da3-2d1faaa9e3c7
019f4bd9-2005-7ee2-98b8-02b7de9ac478
019f4bd9-2005-7ff8-8208-e4039a2b1089

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)

1f17c54e-4f42-6e20-85ef-4cf95d479851
1f17c54e-4f42-6fb0-85ef-4cf95d479851
1f17c54e-4f43-6096-85ef-4cf95d479851
1f17c54e-4f43-6168-85ef-4cf95d479851
1f17c54e-4f43-6230-85ef-4cf95d479851
1f17c54e-4f43-62ee-85ef-4cf95d479851
1f17c54e-4f43-63ac-85ef-4cf95d479851
1f17c54e-4f43-646a-85ef-4cf95d479851
1f17c54e-4f43-6528-85ef-4cf95d479851
1f17c54e-4f43-65e6-85ef-4cf95d479851
1f17c54e-4f43-6726-85ef-4cf95d479851
1f17c54e-4f43-67ee-85ef-4cf95d479851
1f17c54e-4f43-68ac-85ef-4cf95d479851
1f17c54e-4f43-696a-85ef-4cf95d479851
1f17c54e-4f43-6a28-85ef-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)

e4f43afa-7c54-11f1-85ef-4cf95d479851
e4f43b68-7c54-11f1-85ef-4cf95d479851
e4f43bcc-7c54-11f1-85ef-4cf95d479851
e4f43c30-7c54-11f1-85ef-4cf95d479851
e4f43c94-7c54-11f1-85ef-4cf95d479851
e4f43cf8-7c54-11f1-85ef-4cf95d479851
e4f43dca-7c54-11f1-85ef-4cf95d479851
e4f43e42-7c54-11f1-85ef-4cf95d479851
e4f43ea6-7c54-11f1-85ef-4cf95d479851
e4f43f0a-7c54-11f1-85ef-4cf95d479851
e4f43f6e-7c54-11f1-85ef-4cf95d479851
e4f43fd2-7c54-11f1-85ef-4cf95d479851
e4f44036-7c54-11f1-85ef-4cf95d479851
e4f4409a-7c54-11f1-85ef-4cf95d479851
e4f440f4-7c54-11f1-85ef-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)

d5658c30-c202-8f0b-87ea-5ce32bd83b97
658a8d30-c202-8f0b-87ea-5ce32bd83b97
b2dc8e30-c202-8f0b-87ea-5ce32bd83b97
18bf8f30-c202-8f0b-87ea-5ce32bd83b97
b1329030-c202-8f0b-87ea-5ce32bd83b97
30b79230-c202-8f0b-87ea-5ce32bd83b97
6c839330-c202-8f0b-87ea-5ce32bd83b97
7c7e9430-c202-8f0b-87ea-5ce32bd83b97
ffc89530-c202-8f0b-87ea-5ce32bd83b97
1d499630-c202-8f0b-87ea-5ce32bd83b97
99c49730-c202-8f0b-87ea-5ce32bd83b97
096a9830-c202-8f0b-87ea-5ce32bd83b97
aa5f9930-c202-8f0b-87ea-5ce32bd83b97
5e7a9a30-c202-8f0b-87ea-5ce32bd83b97
53509b30-c202-8f0b-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)

b295ce85-cf2f-41f9-b6dd-4b664d359102
f3728f5d-17c8-4927-bf8c-9959629b6890
88327bde-1df9-4cf8-b1bb-53eacc7cc01f
95e2cde3-8437-4973-ad51-5a506504c19b
7acf6148-11ff-4d98-a59c-6fc93ad84e37
0106001a-e430-4425-8999-b9f73d1975d2
796c1976-6772-4d6c-b4fb-53158f1e2b8f
5c60b3b9-fd20-46c8-a157-c00e7e28631c
350bd424-c873-483f-a1e1-4a313f6fb699
9d26fe42-d1f5-43f2-ba14-4f75dc4934d3
45ce4a2f-0ee9-421b-8017-d04fb25d0e50
7e4fdf84-b7a1-4b7d-9831-9a10fd7f67a1
8e5567ea-fea4-493b-b8c9-033abbcc7f32
30f5a159-9da5-49e2-b294-a66adf8b1fe7
9d2045fe-5f8d-46f4-a0c3-8ae2b7459a9e

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: