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)

019da2b8-efa9-7d5d-a988-c028f3def81d
019da2b8-efa9-7f07-8c5a-5d64fed7ce2e
019da2b8-efaa-7052-adea-0f388e4b01fa
019da2b8-efaa-7179-9fce-642009b2fe4c
019da2b8-efaa-729c-b045-5b9b24adc8fe
019da2b8-efaa-73bb-8e40-f04a379f7fb5
019da2b8-efaa-74da-94c7-95f67d1846e5
019da2b8-efaa-75f8-b2fe-901be19bad7b
019da2b8-efaa-7713-ae70-647effd5dd25
019da2b8-efaa-7832-81f0-fb908a84b8f3
019da2b8-efaa-7950-91a2-164a7b0d0969
019da2b8-efaa-7a6f-8bfd-5b0e78532ca2
019da2b8-efaa-7b8a-b82a-baa9a7baf7e5
019da2b8-efaa-7cad-936b-c5e320df81d0
019da2b8-efaa-7dcb-8346-3e470bbe3c59

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)

1f13b766-b934-67ba-9914-4cf95d479851
1f13b766-b934-695e-9914-4cf95d479851
1f13b766-b934-6a58-9914-4cf95d479851
1f13b766-b934-6b34-9914-4cf95d479851
1f13b766-b934-6c06-9914-4cf95d479851
1f13b766-b934-6cd8-9914-4cf95d479851
1f13b766-b934-6db4-9914-4cf95d479851
1f13b766-b934-6e7c-9914-4cf95d479851
1f13b766-b934-6f4e-9914-4cf95d479851
1f13b766-b935-6020-9914-4cf95d479851
1f13b766-b935-6160-9914-4cf95d479851
1f13b766-b935-623c-9914-4cf95d479851
1f13b766-b935-630e-9914-4cf95d479851
1f13b766-b935-63d6-9914-4cf95d479851
1f13b766-b935-64a8-9914-4cf95d479851

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)

f1db9190-211c-400d-8ae3-47f54f8fe31f
9733ace9-4562-4e1e-8f2f-f87b3efb7d14
2723886c-a566-438e-bcd0-8595ea83a288
71edfb49-fa49-49f3-b417-e6ca276f17e5
7d11891a-84f0-45d7-8b68-77d9305b7023
7394c11f-91ef-4c7a-b19f-15fcc490d1ee
be106b3c-4410-4ce5-a300-b6f4c1337307
ecf14b68-b6db-423b-b91f-e750a04749c6
a93cc760-dc49-4889-bdf9-cb93e366ce70
342bae1c-99e0-463c-8c38-74441247e2cf
8cea1b90-86c7-4b29-9013-5c3a74c7de69
25f5a8b8-da3c-44f5-8ad3-7417c72b8152
d895b4ad-6418-479a-bd38-6c3be72dcb53
d42a18b4-91d1-48f0-90e3-12ec3922a9b7
68dde48e-6ac0-442f-b83d-7655d27d4154

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)

6b9359da-3b76-11f1-9914-4cf95d479851
6b935a3e-3b76-11f1-9914-4cf95d479851
6b935aa2-3b76-11f1-9914-4cf95d479851
6b935b10-3b76-11f1-9914-4cf95d479851
6b935b74-3b76-11f1-9914-4cf95d479851
6b935bd8-3b76-11f1-9914-4cf95d479851
6b935c3c-3b76-11f1-9914-4cf95d479851
6b935c96-3b76-11f1-9914-4cf95d479851
6b935cfa-3b76-11f1-9914-4cf95d479851
6b935d54-3b76-11f1-9914-4cf95d479851
6b935db8-3b76-11f1-9914-4cf95d479851
6b935e12-3b76-11f1-9914-4cf95d479851
6b935e80-3b76-11f1-9914-4cf95d479851
6b935ee4-3b76-11f1-9914-4cf95d479851
6b935f48-3b76-11f1-9914-4cf95d479851

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)

b9483802-4905-8c06-87ea-5ce32bd83b97
643a3902-4905-8c06-87ea-5ce32bd83b97
bba03a02-4905-8c06-87ea-5ce32bd83b97
19fe3b02-4905-8c06-87ea-5ce32bd83b97
50c13c02-4905-8c06-87ea-5ce32bd83b97
1a5e3d02-4905-8c06-87ea-5ce32bd83b97
5a533e02-4905-8c06-87ea-5ce32bd83b97
c8ac3f02-4905-8c06-87ea-5ce32bd83b97
e6434002-4905-8c06-87ea-5ce32bd83b97
77d24102-4905-8c06-87ea-5ce32bd83b97
ae724202-4905-8c06-87ea-5ce32bd83b97
6e2a4302-4905-8c06-87ea-5ce32bd83b97
b7174402-4905-8c06-87ea-5ce32bd83b97
d1214502-4905-8c06-87ea-5ce32bd83b97
87a84702-4905-8c06-87ea-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: