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)

019b8a36-285d-789c-82cf-64c7b089cece
019b8a36-285d-7a2e-a9b3-515616ab5681
019b8a36-285d-7b71-9085-0277afbab0bf
019b8a36-285d-7c90-9aab-9c239fc3a94c
019b8a36-285d-7daf-8899-179c51acb173
019b8a36-285d-7ecd-87f5-acb79caf4611
019b8a36-285d-7fec-a33d-7d5d203b73c3
019b8a36-285e-7107-9ad4-696e154d19c6
019b8a36-285e-7221-9300-1b3c8be44d4e
019b8a36-285e-7340-9ef7-a8044fd11389
019b8a36-285e-745b-ab28-f1f4f3d1fccc
019b8a36-285e-7579-bce8-b412df774cfb
019b8a36-285e-7698-ae41-c8fc9bf6c07e
019b8a36-285e-77af-a156-4d65a737a753
019b8a36-285e-78cd-9b50-db353986e8aa

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)

1f0e998f-70a3-6130-9117-4cf95d479851
1f0e998f-70a3-62d4-9117-4cf95d479851
1f0e998f-70a3-63ce-9117-4cf95d479851
1f0e998f-70a3-64a0-9117-4cf95d479851
1f0e998f-70a3-6572-9117-4cf95d479851
1f0e998f-70a3-663a-9117-4cf95d479851
1f0e998f-70a3-670c-9117-4cf95d479851
1f0e998f-70a3-67d4-9117-4cf95d479851
1f0e998f-70a3-68a6-9117-4cf95d479851
1f0e998f-70a3-6978-9117-4cf95d479851
1f0e998f-70a3-6ab8-9117-4cf95d479851
1f0e998f-70a3-6b94-9117-4cf95d479851
1f0e998f-70a3-6c5c-9117-4cf95d479851
1f0e998f-70a3-6d24-9117-4cf95d479851
1f0e998f-70a3-6dec-9117-4cf95d479851

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)

4f164523-2eac-4d02-99d1-9e120aba5d5b
a00de36b-1be4-464d-bc97-ff0df309522f
79acd6e1-8312-4cb7-902c-1c3a2c154b1d
bae55b79-6a0d-4820-8563-fd3e4582b7af
1cff84dd-082f-470d-8d28-637f2fbf7f0b
b1ea8e06-4d84-4457-965d-a935e78968b8
5705bcf4-694e-4da0-ba25-098da5cb9f28
2776c8de-a5ce-4194-9721-0fcfb55a1bfd
cde1b6f2-d61f-4e4c-9fd0-1d38656e847b
bffc7062-ba9c-4c34-8218-439a50911145
ab0e5335-271e-4c6c-8fc9-dbd5e3927cf7
fa68678e-7f00-4fba-9e59-7ee5e37004c9
e4a8bf46-7bb4-44fa-81ed-307ea886a59d
36ab7daf-660e-4191-b5df-efd6940fc301
b718b539-61d8-42ed-b062-1895ac6f5864

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)

f70a43b4-e998-11f0-9117-4cf95d479851
f70a4422-e998-11f0-9117-4cf95d479851
f70a4486-e998-11f0-9117-4cf95d479851
f70a44e0-e998-11f0-9117-4cf95d479851
f70a4544-e998-11f0-9117-4cf95d479851
f70a45b2-e998-11f0-9117-4cf95d479851
f70a4616-e998-11f0-9117-4cf95d479851
f70a467a-e998-11f0-9117-4cf95d479851
f70a46de-e998-11f0-9117-4cf95d479851
f70a4742-e998-11f0-9117-4cf95d479851
f70a47a6-e998-11f0-9117-4cf95d479851
f70a4814-e998-11f0-9117-4cf95d479851
f70a4878-e998-11f0-9117-4cf95d479851
f70a48dc-e998-11f0-9117-4cf95d479851
f70a4940-e998-11f0-9117-4cf95d479851

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)

96e1be2b-4504-8400-87ea-5ce32bd83b97
fb58bf2b-4504-8400-87ea-5ce32bd83b97
f639c02b-4504-8400-87ea-5ce32bd83b97
07a0c12b-4504-8400-87ea-5ce32bd83b97
9fddc22b-4504-8400-87ea-5ce32bd83b97
e427c32b-4504-8400-87ea-5ce32bd83b97
dfa2c42b-4504-8400-87ea-5ce32bd83b97
d716c52b-4504-8400-87ea-5ce32bd83b97
5db0c62b-4504-8400-87ea-5ce32bd83b97
867cc72b-4504-8400-87ea-5ce32bd83b97
209bc82b-4504-8400-87ea-5ce32bd83b97
6053c92b-4504-8400-87ea-5ce32bd83b97
54e6ca2b-4504-8400-87ea-5ce32bd83b97
d6a0cb2b-4504-8400-87ea-5ce32bd83b97
4323cc2b-4504-8400-87ea-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: