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)

0197c912-509f-7a94-804d-3beaccefd2e2
0197c912-509f-7c2e-81e9-20011466e494
0197c912-509f-7d6d-a48f-a8785b82d475
0197c912-509f-7e94-a7a1-101701de449b
0197c912-509f-7fb3-be8c-5ef90fcd76f2
0197c912-50a0-70cd-9077-5ccf81bc890b
0197c912-50a0-71ec-9f5a-97e1c44ce57a
0197c912-50a0-730b-a09d-90f109962cb5
0197c912-50a0-7425-be9e-32a4d96a4f5f
0197c912-50a0-7540-8abb-c01fdc10fb52
0197c912-50a0-765f-a2f3-712d59116307
0197c912-50a0-777d-a37d-1d730ef3998f
0197c912-50a0-7898-8f8c-8cbf2503458a
0197c912-50a0-79b7-9ff5-88b2c0448d88
0197c912-50a0-7ad5-b45a-ba75a22621e1

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)

1f056f06-eeec-6846-99e7-4cf95d479851
1f056f06-eeec-69e0-99e7-4cf95d479851
1f056f06-eeec-6ad0-99e7-4cf95d479851
1f056f06-eeec-6b98-99e7-4cf95d479851
1f056f06-eeec-6c6a-99e7-4cf95d479851
1f056f06-eeec-6d32-99e7-4cf95d479851
1f056f06-eeec-6df0-99e7-4cf95d479851
1f056f06-eeec-6eae-99e7-4cf95d479851
1f056f06-eeec-6f76-99e7-4cf95d479851
1f056f06-eeed-603e-99e7-4cf95d479851
1f056f06-eeed-617e-99e7-4cf95d479851
1f056f06-eeed-6250-99e7-4cf95d479851
1f056f06-eeed-6318-99e7-4cf95d479851
1f056f06-eeed-63e0-99e7-4cf95d479851
1f056f06-eeed-64a8-99e7-4cf95d479851

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)

7665d596-f75f-4bfb-a061-cf3891cd74a1
83c664b5-6835-4d79-ad96-a0b3e2435d46
b466d2e3-b3db-452a-ba1c-9677da19f660
60876fd3-f521-4beb-855f-bed38eb5c766
f3bf942c-cd40-45db-a4e7-5dac2b7ff789
e40f4acd-46c8-4da5-93c4-8eceb945f248
229dac08-6fa7-4ef0-80e9-51119489b6e9
ff4eeaf9-5b96-4734-8fd2-1fcdef8e0ec2
05995c23-b321-4fb2-9a84-926e600ce2d7
8bcf6c0e-4db9-488e-ad3a-4219af55b58c
bab05f2e-d8d3-4502-86ca-f0d1072701b3
cf273068-be85-4ce4-9236-1ddcf6cf51a8
be918e4a-f13a-4d2a-a1ac-ee54415043c7
1dd2294c-6e7e-48e4-8b63-1e249d97d4c3
a0d513dc-e096-4529-9cff-d2978b5706b8

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)

6eeed9d0-56f0-11f0-99e7-4cf95d479851
6eeeda34-56f0-11f0-99e7-4cf95d479851
6eeeda98-56f0-11f0-99e7-4cf95d479851
6eeedb06-56f0-11f0-99e7-4cf95d479851
6eeedb6a-56f0-11f0-99e7-4cf95d479851
6eeedbce-56f0-11f0-99e7-4cf95d479851
6eeedc32-56f0-11f0-99e7-4cf95d479851
6eeedc96-56f0-11f0-99e7-4cf95d479851
6eeedcfa-56f0-11f0-99e7-4cf95d479851
6eeedd5e-56f0-11f0-99e7-4cf95d479851
6eeeddb8-56f0-11f0-99e7-4cf95d479851
6eeede26-56f0-11f0-99e7-4cf95d479851
6eeede8a-56f0-11f0-99e7-4cf95d479851
6eeedee4-56f0-11f0-99e7-4cf95d479851
6eeedf5c-56f0-11f0-99e7-4cf95d479851

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)

e4d62d1e-b300-870b-87e9-5ce32bd83b97
24152e1e-b300-870b-87e9-5ce32bd83b97
de562f1e-b300-870b-87e9-5ce32bd83b97
1088301e-b300-870b-87e9-5ce32bd83b97
ee24311e-b300-870b-87e9-5ce32bd83b97
833e321e-b300-870b-87e9-5ce32bd83b97
5079331e-b300-870b-87e9-5ce32bd83b97
eea6351e-b300-870b-87e9-5ce32bd83b97
3ddc361e-b300-870b-87e9-5ce32bd83b97
741d371e-b300-870b-87e9-5ce32bd83b97
e41c381e-b300-870b-87e9-5ce32bd83b97
5f5a391e-b300-870b-87e9-5ce32bd83b97
38053a1e-b300-870b-87e9-5ce32bd83b97
1ee03b1e-b300-870b-87e9-5ce32bd83b97
f5a73c1e-b300-870b-87e9-5ce32bd83b97

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: