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)

019ac5b6-6f6a-73e8-9eff-8da3d17e2899
019ac5b6-6f6a-757d-8579-4497656035d5
019ac5b6-6f6a-76c1-9ff6-986af7ec3338
019ac5b6-6f6a-77dc-8669-73320d362d98
019ac5b6-6f6a-78b1-b9e8-45a13d231748
019ac5b6-6f6a-79cb-95ac-0c0354837990
019ac5b6-6f6a-7ae2-90f8-b482ec99aa32
019ac5b6-6f6a-7bf8-a06b-b1c78c805a36
019ac5b6-6f6a-7d38-adcd-622b9584cc82
019ac5b6-6f6a-7e7f-913c-3fe345a9f085
019ac5b6-6f6a-7fb3-8b8f-fa537e6e2250
019ac5b6-6f6b-70c9-9228-1693d382622d
019ac5b6-6f6b-71e4-9c33-d79f9a86e240
019ac5b6-6f6b-72fa-9842-ab016aa887c8
019ac5b6-6f6b-7411-b3ac-5132f7850c53

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)

1f0cb9d3-9e19-6170-a8b7-4cf95d479851
1f0cb9d3-9e19-630a-a8b7-4cf95d479851
1f0cb9d3-9e19-63f0-a8b7-4cf95d479851
1f0cb9d3-9e19-64c2-a8b7-4cf95d479851
1f0cb9d3-9e19-6580-a8b7-4cf95d479851
1f0cb9d3-9e19-6648-a8b7-4cf95d479851
1f0cb9d3-9e19-6706-a8b7-4cf95d479851
1f0cb9d3-9e19-67c4-a8b7-4cf95d479851
1f0cb9d3-9e19-6882-a8b7-4cf95d479851
1f0cb9d3-9e19-6940-a8b7-4cf95d479851
1f0cb9d3-9e19-6a80-a8b7-4cf95d479851
1f0cb9d3-9e19-6b48-a8b7-4cf95d479851
1f0cb9d3-9e19-6c10-a8b7-4cf95d479851
1f0cb9d3-9e19-6cce-a8b7-4cf95d479851
1f0cb9d3-9e19-6d8c-a8b7-4cf95d479851

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)

133d29e1-cc19-4a40-b9db-03249da13e81
729ea051-c495-400d-a343-b028cadfa373
0d3b1140-45c3-4a52-a4ab-e47983a8d8c9
3a7464bd-f70e-42e0-a3c2-d55b61b28c18
ee9813a3-6abe-4655-8937-a980e17b0f47
5eac483a-7641-409b-855b-8a6ad644eff3
007fbc02-bfcd-48c1-a72f-41a24531645d
da869b4c-e2b8-4478-ad35-ca2499f4e90d
5467f6e7-1f2d-4d39-85f7-2d23b73cd1da
7c683d8a-3c79-4b2f-9b8c-64289f4d3f5e
fd5694c0-557c-4199-813c-c2e52aeb82e8
d8818809-05eb-4ec2-bb7d-6c5fcd1d23fc
e4fcf076-7a88-4352-91a5-17901763597b
73d309b4-dd37-401e-933e-ce06948f23ef
93e59687-04ae-400a-99ff-8db65980ce8e

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)

39e1a2aa-cb9d-11f0-a8b7-4cf95d479851
39e1a30e-cb9d-11f0-a8b7-4cf95d479851
39e1a372-cb9d-11f0-a8b7-4cf95d479851
39e1a3cc-cb9d-11f0-a8b7-4cf95d479851
39e1a430-cb9d-11f0-a8b7-4cf95d479851
39e1a48a-cb9d-11f0-a8b7-4cf95d479851
39e1a4e4-cb9d-11f0-a8b7-4cf95d479851
39e1a53e-cb9d-11f0-a8b7-4cf95d479851
39e1a5a2-cb9d-11f0-a8b7-4cf95d479851
39e1a606-cb9d-11f0-a8b7-4cf95d479851
39e1a660-cb9d-11f0-a8b7-4cf95d479851
39e1a6ce-cb9d-11f0-a8b7-4cf95d479851
39e1a732-cb9d-11f0-a8b7-4cf95d479851
39e1a796-cb9d-11f0-a8b7-4cf95d479851
39e1a7f0-cb9d-11f0-a8b7-4cf95d479851

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)

2f09fc26-6403-8b14-87e9-5ce32bd83b97
de1ffd26-6403-8b14-87e9-5ce32bd83b97
6303fe26-6403-8b14-87e9-5ce32bd83b97
930b0027-6403-8b14-87e9-5ce32bd83b97
f2bb0127-6403-8b14-87e9-5ce32bd83b97
87b40227-6403-8b14-87e9-5ce32bd83b97
0b5d0327-6403-8b14-87e9-5ce32bd83b97
a23e0427-6403-8b14-87e9-5ce32bd83b97
0a860527-6403-8b14-87e9-5ce32bd83b97
64740627-6403-8b14-87e9-5ce32bd83b97
340b0727-6403-8b14-87e9-5ce32bd83b97
c9410827-6403-8b14-87e9-5ce32bd83b97
1b210927-6403-8b14-87e9-5ce32bd83b97
1b000a27-6403-8b14-87e9-5ce32bd83b97
fbef0b27-6403-8b14-87e9-5ce32bd83b97

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: