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)

019c26ad-af4c-7cbd-8a7a-cda3db61cae6
019c26ad-af4c-7e57-807b-a7280bbe4fcc
019c26ad-af4c-7f9a-a4e1-cb32c0419f26
019c26ad-af4d-70b9-bc72-224ef3363fdb
019c26ad-af4d-71d8-91d8-4b30b370f89d
019c26ad-af4d-72f6-b436-83d9fb04cc7b
019c26ad-af4d-7411-ba1e-59dbb8b7d4c9
019c26ad-af4d-7530-bcdd-921838aac2cf
019c26ad-af4d-764a-8009-d11c444112b7
019c26ad-af4d-7765-9e4b-b569b1eef00b
019c26ad-af4d-7884-bdfd-bae94b8f58d1
019c26ad-af4d-799e-a5cc-65e1f42840d4
019c26ad-af4d-7abd-ac62-1c79fa5ab8bb
019c26ad-af4d-7bd8-8075-6308bc6c80fd
019c26ad-af4d-7cf2-a736-67786d4c0205

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)

1f10178f-4111-632a-a256-4cf95d479851
1f10178f-4111-64ba-a256-4cf95d479851
1f10178f-4111-65a0-a256-4cf95d479851
1f10178f-4111-6672-a256-4cf95d479851
1f10178f-4111-6744-a256-4cf95d479851
1f10178f-4111-680c-a256-4cf95d479851
1f10178f-4111-68d4-a256-4cf95d479851
1f10178f-4111-6992-a256-4cf95d479851
1f10178f-4111-6a50-a256-4cf95d479851
1f10178f-4111-6b18-a256-4cf95d479851
1f10178f-4111-6c58-a256-4cf95d479851
1f10178f-4111-6d48-a256-4cf95d479851
1f10178f-4111-6eba-a256-4cf95d479851
1f10178f-4112-6022-a256-4cf95d479851
1f10178f-4112-6180-a256-4cf95d479851

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)

ebd84bad-f240-4edf-8bc6-69a277ad45c9
4da2a4b3-d8e9-4d8d-8a58-93711aedd082
86747a53-2c03-490f-aec9-307ab0ed5485
922f2292-21c4-4aec-8898-1d7df7dc4650
c1814147-f87c-4853-b8bf-9a403a3f24db
66ad6229-7f46-4121-bf04-632f7fa47822
e97cb20b-ae57-47b5-b24d-46fb11ee4386
bd067e89-d7fc-4a91-a93b-2de1e9fa4227
86eb377f-798a-4335-ab8d-9659b2aa1a3f
248986ec-6dec-4798-b31e-00c3e8378c85
19fa3a84-c62f-491a-9741-391082799296
d25eeb58-771a-4bfd-89a4-f240a18ef62b
492a2006-6f17-4851-a65f-e1d6b116d73c
21cf649e-95a9-4785-b5ef-6714432e8e72
7477c355-3dbc-4c47-b898-ec15d1ec780d

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)

f41128b0-0178-11f1-a256-4cf95d479851
f4112946-0178-11f1-a256-4cf95d479851
f41129e6-0178-11f1-a256-4cf95d479851
f4112a72-0178-11f1-a256-4cf95d479851
f4112b08-0178-11f1-a256-4cf95d479851
f4112b94-0178-11f1-a256-4cf95d479851
f4112c16-0178-11f1-a256-4cf95d479851
f4112cac-0178-11f1-a256-4cf95d479851
f4112d38-0178-11f1-a256-4cf95d479851
f4112dc4-0178-11f1-a256-4cf95d479851
f4112e50-0178-11f1-a256-4cf95d479851
f4112edc-0178-11f1-a256-4cf95d479851
f4112f72-0178-11f1-a256-4cf95d479851
f4112ffe-0178-11f1-a256-4cf95d479851
f411308a-0178-11f1-a256-4cf95d479851

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)

aa4fc402-cd00-8302-87ea-5ce32bd83b97
1ca8c502-cd00-8302-87ea-5ce32bd83b97
8672c602-cd00-8302-87ea-5ce32bd83b97
0b6ec702-cd00-8302-87ea-5ce32bd83b97
a5dcc802-cd00-8302-87ea-5ce32bd83b97
a41ac902-cd00-8302-87ea-5ce32bd83b97
7664ca02-cd00-8302-87ea-5ce32bd83b97
2eeecb02-cd00-8302-87ea-5ce32bd83b97
606bcc02-cd00-8302-87ea-5ce32bd83b97
8df5cd02-cd00-8302-87ea-5ce32bd83b97
33d6ce02-cd00-8302-87ea-5ce32bd83b97
0ec8cf02-cd00-8302-87ea-5ce32bd83b97
1157d002-cd00-8302-87ea-5ce32bd83b97
00b6d102-cd00-8302-87ea-5ce32bd83b97
1eebd202-cd00-8302-87ea-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: