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)

019d3ef5-3972-7cc5-9993-a035299f0d57
019d3ef5-3972-7e73-98c3-e2d0b4983ed1
019d3ef5-3972-7fb7-b747-26d030e15055
019d3ef5-3973-70da-a5e0-0b7c7210f7bd
019d3ef5-3973-71f4-86a6-52a849344cda
019d3ef5-3973-730f-813d-76eaf3019317
019d3ef5-3973-7425-aafb-c422506a8984
019d3ef5-3973-753c-9df8-a894bdc2b9e9
019d3ef5-3973-7657-8700-7ad0c551c466
019d3ef5-3973-7771-8a3a-240a62e09da0
019d3ef5-3973-788c-a8a8-f21d02f76e5f
019d3ef5-3973-79a2-94e9-a0c064b9b96a
019d3ef5-3973-7abd-8962-ceb1edec5c51
019d3ef5-3973-7bd3-9e8d-421c7acc4bb3
019d3ef5-3973-7cee-b654-48223162af76

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)

1f12c3d5-e958-60e8-be69-4cf95d479851
1f12c3d5-e958-6296-be69-4cf95d479851
1f12c3d5-e958-637c-be69-4cf95d479851
1f12c3d5-e958-644e-be69-4cf95d479851
1f12c3d5-e958-6516-be69-4cf95d479851
1f12c3d5-e958-65de-be69-4cf95d479851
1f12c3d5-e958-66a6-be69-4cf95d479851
1f12c3d5-e958-6764-be69-4cf95d479851
1f12c3d5-e958-6822-be69-4cf95d479851
1f12c3d5-e958-699e-be69-4cf95d479851
1f12c3d5-e958-6b06-be69-4cf95d479851
1f12c3d5-e958-6bce-be69-4cf95d479851
1f12c3d5-e958-6c8c-be69-4cf95d479851
1f12c3d5-e958-6d4a-be69-4cf95d479851
1f12c3d5-e958-6e08-be69-4cf95d479851

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)

b846279a-2666-45ab-b9e7-bf84197fe3f4
96dac1fc-f7b6-4c79-a9f6-233794b13269
707a12a3-9e2b-4a3f-8cc3-9f03f5069206
cdf546bf-46e9-4869-8eea-dcaa407aeadd
7d3b63ef-93ed-4cab-8e29-1b8c787addc1
453545cd-728e-4fae-b12c-7c145917e5ab
ff078f5b-a9d3-4aca-b670-967092622215
5eaf23db-1503-486c-9540-0b2b30f9a986
2b84f0e3-a84c-4c6a-b12c-1d02e41a54c7
89380422-26e7-4989-9d56-5c1a126aa1a0
97ceb6f6-460c-4387-bb29-d54c1fb4dfa2
31c3e20c-2041-468f-8897-1fc58fe05184
6129baf7-2f73-4dbd-a963-31afe3b5d93c
fc4e9cc5-1134-4ad7-b485-2d17021bddea
eb2e2bd8-381d-48bc-9591-ee0c58c0d0c0

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)

5e95931c-2c3d-11f1-be69-4cf95d479851
5e959394-2c3d-11f1-be69-4cf95d479851
5e959402-2c3d-11f1-be69-4cf95d479851
5e959470-2c3d-11f1-be69-4cf95d479851
5e9594d4-2c3d-11f1-be69-4cf95d479851
5e959538-2c3d-11f1-be69-4cf95d479851
5e9595a6-2c3d-11f1-be69-4cf95d479851
5e95961e-2c3d-11f1-be69-4cf95d479851
5e95968c-2c3d-11f1-be69-4cf95d479851
5e9596fa-2c3d-11f1-be69-4cf95d479851
5e95975e-2c3d-11f1-be69-4cf95d479851
5e9597b8-2c3d-11f1-be69-4cf95d479851
5e95981c-2c3d-11f1-be69-4cf95d479851
5e959880-2c3d-11f1-be69-4cf95d479851
5e9598e4-2c3d-11f1-be69-4cf95d479851

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)

b0d2ab33-3003-8905-87ea-5ce32bd83b97
ffd8ac33-3003-8905-87ea-5ce32bd83b97
42d7ad33-3003-8905-87ea-5ce32bd83b97
c6e1ae33-3003-8905-87ea-5ce32bd83b97
8b19af33-3003-8905-87ea-5ce32bd83b97
1506b033-3003-8905-87ea-5ce32bd83b97
119cb133-3003-8905-87ea-5ce32bd83b97
51bbb233-3003-8905-87ea-5ce32bd83b97
7e05b333-3003-8905-87ea-5ce32bd83b97
2b7bb433-3003-8905-87ea-5ce32bd83b97
8173b533-3003-8905-87ea-5ce32bd83b97
e968b633-3003-8905-87ea-5ce32bd83b97
b8f4b733-3003-8905-87ea-5ce32bd83b97
3c1fb833-3003-8905-87ea-5ce32bd83b97
d351b933-3003-8905-87ea-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: