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)

019c095b-07a7-7205-bf91-116317f1a06c
019c095b-07a7-739a-a9f4-9b75c9258312
019c095b-07a7-74da-a130-cf0710e309d9
019c095b-07a7-764a-a18b-8af672ea0a26
019c095b-07a7-7771-99ec-73a11f524dbd
019c095b-07a7-788c-9d2f-42425fc41ab3
019c095b-07a7-79a6-b04d-41803676e684
019c095b-07a7-7ac1-b4be-dcadf6a4ef4e
019c095b-07a7-7bdc-9985-e882a3259392
019c095b-07a7-7cfa-8527-baad935a291c
019c095b-07a7-7e15-8366-29f6165a07a9
019c095b-07a7-7f30-bce1-210ddf29120b
019c095b-07a8-704e-8b92-26ae38fe79cc
019c095b-07a8-7169-8e42-32feb919ad23
019c095b-07a8-7288-85a3-aef00617a679

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)

1f0fcff8-75c5-6ca8-af45-4cf95d479851
1f0fcff8-75c5-6e38-af45-4cf95d479851
1f0fcff8-75c5-6f28-af45-4cf95d479851
1f0fcff8-75c6-6004-af45-4cf95d479851
1f0fcff8-75c6-60d6-af45-4cf95d479851
1f0fcff8-75c6-619e-af45-4cf95d479851
1f0fcff8-75c6-6266-af45-4cf95d479851
1f0fcff8-75c6-632e-af45-4cf95d479851
1f0fcff8-75c6-63f6-af45-4cf95d479851
1f0fcff8-75c6-64be-af45-4cf95d479851
1f0fcff8-75c6-6630-af45-4cf95d479851
1f0fcff8-75c6-670c-af45-4cf95d479851
1f0fcff8-75c6-67d4-af45-4cf95d479851
1f0fcff8-75c6-68a6-af45-4cf95d479851
1f0fcff8-75c6-696e-af45-4cf95d479851

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)

989d5cc4-1018-458f-9e6e-4d6810fc19db
ce807b3a-a435-43bd-b688-d38aec99ca57
fddae0a3-8048-4701-9b7d-b4af9ae84f02
01dbbbee-1313-47fe-b2c8-70aa59bfbb3a
d1f9be83-aaab-4859-b718-f5011838f979
76227c41-7d71-4a9a-80ea-dee19890f5e2
65cb40e4-d2e9-4874-bf43-4346febff07a
54ef273c-d635-41b5-bb71-8b196d895ac5
7bd27a8e-9bfa-42f5-b565-e5daf44a17ce
4d367bf5-a04c-4c0e-967e-1fade6d49721
b6ec34bd-5b86-4837-967a-09ba1b5820ee
d2eab629-d252-47fa-accd-38e214993a0e
a2dd6e1b-d700-4ed3-9def-b6c9ecf519ce
b59d001a-f00a-4464-9bdf-de3af7cdc4b5
36b8557d-b447-4210-8f35-a37c42ce58a2

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)

875c6ea0-fcff-11f0-af45-4cf95d479851
875c6f0e-fcff-11f0-af45-4cf95d479851
875c6f72-fcff-11f0-af45-4cf95d479851
875c6fd6-fcff-11f0-af45-4cf95d479851
875c7044-fcff-11f0-af45-4cf95d479851
875c70a8-fcff-11f0-af45-4cf95d479851
875c7102-fcff-11f0-af45-4cf95d479851
875c7166-fcff-11f0-af45-4cf95d479851
875c71d4-fcff-11f0-af45-4cf95d479851
875c7238-fcff-11f0-af45-4cf95d479851
875c729c-fcff-11f0-af45-4cf95d479851
875c730a-fcff-11f0-af45-4cf95d479851
875c7378-fcff-11f0-af45-4cf95d479851
875c73e6-fcff-11f0-af45-4cf95d479851
875c7454-fcff-11f0-af45-4cf95d479851

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)

9b2ca12e-8502-8d01-87ea-5ce32bd83b97
f0b3a32e-8502-8d01-87ea-5ce32bd83b97
aeefa42e-8502-8d01-87ea-5ce32bd83b97
febaa52e-8502-8d01-87ea-5ce32bd83b97
16d7a62e-8502-8d01-87ea-5ce32bd83b97
bf2fa72e-8502-8d01-87ea-5ce32bd83b97
6244a82e-8502-8d01-87ea-5ce32bd83b97
5fc7a92e-8502-8d01-87ea-5ce32bd83b97
07aeaa2e-8502-8d01-87ea-5ce32bd83b97
0676ab2e-8502-8d01-87ea-5ce32bd83b97
d96cac2e-8502-8d01-87ea-5ce32bd83b97
78c8ad2e-8502-8d01-87ea-5ce32bd83b97
c0e2ae2e-8502-8d01-87ea-5ce32bd83b97
d71caf2e-8502-8d01-87ea-5ce32bd83b97
5201b02e-8502-8d01-87ea-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: