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)

019c0863-7561-704a-982b-6ede165fa5ea
019c0863-7562-71f4-9688-d8f5088f879a
019c0863-7562-7334-b0d1-a484afc72bec
019c0863-7562-7457-b21c-b898ed3b866a
019c0863-7562-7571-b5de-b4fe8d94af82
019c0863-7562-7690-892e-d90498da9ae7
019c0863-7562-77aa-9904-2105369acad7
019c0863-7562-78c5-8b55-c5d98607dc5d
019c0863-7562-79e0-b57c-acbbd1105b22
019c0863-7562-7af6-bbba-448337f1db1b
019c0863-7562-7c19-89a6-c854f60bdae9
019c0863-7562-7d34-af09-f50ca9f20f15
019c0863-7562-7e4e-acea-eea16e52a729
019c0863-7562-7f69-80ec-15fc7251e622
019c0863-7563-7084-afc5-d8ca928505f4

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)

1f0fcd9c-09ab-61c0-af45-4cf95d479851
1f0fcd9c-09ab-635a-af45-4cf95d479851
1f0fcd9c-09ab-644a-af45-4cf95d479851
1f0fcd9c-09ab-6526-af45-4cf95d479851
1f0fcd9c-09ab-65f8-af45-4cf95d479851
1f0fcd9c-09ab-66c0-af45-4cf95d479851
1f0fcd9c-09ab-6792-af45-4cf95d479851
1f0fcd9c-09ab-685a-af45-4cf95d479851
1f0fcd9c-09ab-6922-af45-4cf95d479851
1f0fcd9c-09ab-69f4-af45-4cf95d479851
1f0fcd9c-09ab-6b52-af45-4cf95d479851
1f0fcd9c-09ab-6c24-af45-4cf95d479851
1f0fcd9c-09ab-6cec-af45-4cf95d479851
1f0fcd9c-09ab-6db4-af45-4cf95d479851
1f0fcd9c-09ab-6e7c-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)

6da4ea92-3f20-4fd6-ade8-26bc39c3d4c7
45c6ef16-48aa-4613-b0d6-57c57f48a7d0
837dcb99-43e0-4cbc-bc4a-00da8f9531dd
23241920-fb71-4c43-9cb0-441bda4a5d4c
e03fd4e8-24e0-4600-8c74-acb77a2e1525
985aa387-38de-466f-8b50-2d8727356efc
2ab58fc3-9560-4b55-a192-c6ac9ed7252a
8d34a923-791d-475f-ad06-ff5cc0f26a06
57537bbd-9fa0-47e5-a9e3-4bbc073003d9
9f3f0e1a-7f44-497b-b235-eea0d93ac12b
50cba5a1-26c9-450c-813a-4419c03fd65f
38691d7f-91d6-4bfc-adf6-d85a3ce82788
503a023c-7ce6-4871-a747-d370372e49d4
a557e8f7-9765-4f84-8627-abb634cf35af
261c7f70-0adb-4a64-8f89-ed18b9682a8e

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)

c09ac444-fcd9-11f0-af45-4cf95d479851
c09ac4b2-fcd9-11f0-af45-4cf95d479851
c09ac516-fcd9-11f0-af45-4cf95d479851
c09ac584-fcd9-11f0-af45-4cf95d479851
c09ac5e8-fcd9-11f0-af45-4cf95d479851
c09ac64c-fcd9-11f0-af45-4cf95d479851
c09ac6b0-fcd9-11f0-af45-4cf95d479851
c09ac714-fcd9-11f0-af45-4cf95d479851
c09ac778-fcd9-11f0-af45-4cf95d479851
c09ac7dc-fcd9-11f0-af45-4cf95d479851
c09ac840-fcd9-11f0-af45-4cf95d479851
c09ac8ae-fcd9-11f0-af45-4cf95d479851
c09ac912-fcd9-11f0-af45-4cf95d479851
c09ac976-fcd9-11f0-af45-4cf95d479851
c09ac9e4-fcd9-11f0-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)

1dc9cb15-7701-8d01-87ea-5ce32bd83b97
2afecc15-7701-8d01-87ea-5ce32bd83b97
e3e4cd15-7701-8d01-87ea-5ce32bd83b97
5da5ce15-7701-8d01-87ea-5ce32bd83b97
150acf15-7701-8d01-87ea-5ce32bd83b97
b04cd015-7701-8d01-87ea-5ce32bd83b97
5705d115-7701-8d01-87ea-5ce32bd83b97
8602d215-7701-8d01-87ea-5ce32bd83b97
4abed315-7701-8d01-87ea-5ce32bd83b97
bd6cd415-7701-8d01-87ea-5ce32bd83b97
f171d515-7701-8d01-87ea-5ce32bd83b97
171dd615-7701-8d01-87ea-5ce32bd83b97
659bd715-7701-8d01-87ea-5ce32bd83b97
6ef4d815-7701-8d01-87ea-5ce32bd83b97
15bad915-7701-8d01-87ea-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: