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)

019cf6f5-ae8c-74a0-87ca-7970de9ecdea
019cf6f5-ae8c-769c-8898-92117296759f
019cf6f5-ae8c-77f0-a4d7-d9f4c092ac4b
019cf6f5-ae8c-7917-b50f-2a918946bc4d
019cf6f5-ae8c-7a36-b985-5ac2bd9df832
019cf6f5-ae8c-7b54-bd1b-33dafffc32fb
019cf6f5-ae8c-7c77-a005-87bce2216be2
019cf6f5-ae8c-7d96-9a7d-15a38bbce71d
019cf6f5-ae8c-7eb5-b38d-6ac9c52e7f19
019cf6f5-ae8c-7fcf-a105-dc6970968f5b
019cf6f5-ae8d-70f2-bdc8-d15cb5bb4d35
019cf6f5-ae8d-7211-8300-d2c8b958a9d2
019cf6f5-ae8d-7334-88f3-697666d1310a
019cf6f5-ae8d-7484-b24f-0a715282769d
019cf6f5-ae8d-75d8-9486-c7efdb6ac623

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)

1f12140f-073b-6762-850d-4cf95d479851
1f12140f-073b-697e-850d-4cf95d479851
1f12140f-073b-6a6e-850d-4cf95d479851
1f12140f-073b-6b40-850d-4cf95d479851
1f12140f-073b-6c94-850d-4cf95d479851
1f12140f-073b-6e1a-850d-4cf95d479851
1f12140f-073b-6f96-850d-4cf95d479851
1f12140f-073c-60ea-850d-4cf95d479851
1f12140f-073c-61c6-850d-4cf95d479851
1f12140f-073c-628e-850d-4cf95d479851
1f12140f-073c-63e2-850d-4cf95d479851
1f12140f-073c-64b4-850d-4cf95d479851
1f12140f-073c-657c-850d-4cf95d479851
1f12140f-073c-669e-850d-4cf95d479851
1f12140f-073c-681a-850d-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)

bf68d56b-6756-4937-bdcd-11ae0ffb6642
e6a502ea-2eda-4fb2-92da-17cdc59947aa
5b7c01e1-6423-4ff2-a528-7daf0c07cdf6
9077f71e-9573-43c1-a905-4145d5d2e4e8
af990006-3062-4e10-bd4e-1d020b65280d
cf0f61ad-9929-410b-bcdc-5b41f5f0a449
184c1d6f-9e6b-4168-84ca-931b82210aa3
c8c01c95-5fbb-450d-aba0-20df0094c068
1fa522e4-def6-4949-a221-f643c049e702
5b6af222-a7c2-41e1-b17e-9c9171471311
bae351d4-ac1f-485b-bd1d-cf255e32fab9
a5b8c149-de0b-4e2c-a53d-ec43021e877d
902627b4-da6f-4e9f-ab77-20de8d2f0ef3
3ec50ad5-6b0b-4cd1-a0c0-daf1446ba90a
e851e9cc-dd73-4dcb-ac67-ad3a4bbdb1a6

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)

f073ce5a-2140-11f1-850d-4cf95d479851
f073ced2-2140-11f1-850d-4cf95d479851
f073cf36-2140-11f1-850d-4cf95d479851
f073cf90-2140-11f1-850d-4cf95d479851
f073d008-2140-11f1-850d-4cf95d479851
f073d09e-2140-11f1-850d-4cf95d479851
f073d13e-2140-11f1-850d-4cf95d479851
f073d1f2-2140-11f1-850d-4cf95d479851
f073d288-2140-11f1-850d-4cf95d479851
f073d31e-2140-11f1-850d-4cf95d479851
f073d3b4-2140-11f1-850d-4cf95d479851
f073d44a-2140-11f1-850d-4cf95d479851
f073d4c2-2140-11f1-850d-4cf95d479851
f073d530-2140-11f1-850d-4cf95d479851
f073d594-2140-11f1-850d-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)

1b8a182a-4c03-8b04-87ea-5ce32bd83b97
9b87192a-4c03-8b04-87ea-5ce32bd83b97
47cc1a2a-4c03-8b04-87ea-5ce32bd83b97
f4ed1b2a-4c03-8b04-87ea-5ce32bd83b97
1b061c2a-4c03-8b04-87ea-5ce32bd83b97
71aa1d2a-4c03-8b04-87ea-5ce32bd83b97
c45f1e2a-4c03-8b04-87ea-5ce32bd83b97
62071f2a-4c03-8b04-87ea-5ce32bd83b97
d44a202a-4c03-8b04-87ea-5ce32bd83b97
a525212a-4c03-8b04-87ea-5ce32bd83b97
491a222a-4c03-8b04-87ea-5ce32bd83b97
08b3232a-4c03-8b04-87ea-5ce32bd83b97
f703252a-4c03-8b04-87ea-5ce32bd83b97
a964262a-4c03-8b04-87ea-5ce32bd83b97
6ad0272a-4c03-8b04-87ea-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: