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)

019c8eb8-8171-751f-bcb3-ee3ace63d3e8
019c8eb8-8171-76b5-ab12-d2643531e727
019c8eb8-8171-77f4-8ada-c3edf7d5cc6e
019c8eb8-8171-7917-b96b-9df0a8c4df2a
019c8eb8-8171-7a32-9666-d0ed63e00749
019c8eb8-8171-7b4c-9bc3-96cbb3cd0cbf
019c8eb8-8171-7c6b-b5d8-c8cea29616d9
019c8eb8-8171-7d82-a07c-eab99e5a63f4
019c8eb8-8171-7e9c-94eb-a19a1759952c
019c8eb8-8171-7fb3-b273-b6877eb830fe
019c8eb8-8172-70c9-a73e-be0700645388
019c8eb8-8172-71e8-a0c5-84895b9ff415
019c8eb8-8172-7303-9627-5335a2b0aa72
019c8eb8-8172-741d-8071-2d4a35eff6c2
019c8eb8-8172-7534-87a9-6dbb576486cc

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)

1f111591-ac1c-6556-9e44-4cf95d479851
1f111591-ac1c-66e6-9e44-4cf95d479851
1f111591-ac1c-67c2-9e44-4cf95d479851
1f111591-ac1c-688a-9e44-4cf95d479851
1f111591-ac1c-6948-9e44-4cf95d479851
1f111591-ac1c-6a10-9e44-4cf95d479851
1f111591-ac1c-6ace-9e44-4cf95d479851
1f111591-ac1c-6b8c-9e44-4cf95d479851
1f111591-ac1c-6c40-9e44-4cf95d479851
1f111591-ac1c-6d08-9e44-4cf95d479851
1f111591-ac1c-6e52-9e44-4cf95d479851
1f111591-ac1c-6f10-9e44-4cf95d479851
1f111591-ac1c-6fce-9e44-4cf95d479851
1f111591-ac1d-6082-9e44-4cf95d479851
1f111591-ac1d-6140-9e44-4cf95d479851

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)

ccf6d533-b519-4e8c-a794-eceabc77f7a8
ffcf4617-c6a6-4b23-82b1-bf715958e5d9
b56a8d38-e732-444d-bfd2-94880542bfd7
5aff745c-919f-4cc5-bbdc-b423a5cb5228
8495bf25-c29c-4b5a-b7c2-366d29c4e9fb
28d64fad-4481-4439-b52a-5954180057f4
61f7486b-6a64-4324-b877-2dca95a46ea8
f806ee05-9f6a-44d7-8898-be76143fdffa
6c3d7e89-8afe-4d8d-894c-8e27f55b5336
2327cec0-6440-407a-9e2b-941a76d1be99
20c6b4a4-a261-49b4-bc50-71284b2cedb4
cde4db34-2ee6-4c92-b545-7c82330b9961
104a1b49-1410-445d-a47c-21166856fa1f
31762dd7-51e6-4295-8045-f35c92db94dc
4c935526-d962-4198-a80d-4e1cbb23c364

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)

1ac1d672-1159-11f1-9e44-4cf95d479851
1ac1d6e0-1159-11f1-9e44-4cf95d479851
1ac1d744-1159-11f1-9e44-4cf95d479851
1ac1d7a8-1159-11f1-9e44-4cf95d479851
1ac1d80c-1159-11f1-9e44-4cf95d479851
1ac1d866-1159-11f1-9e44-4cf95d479851
1ac1d8ca-1159-11f1-9e44-4cf95d479851
1ac1d92e-1159-11f1-9e44-4cf95d479851
1ac1d988-1159-11f1-9e44-4cf95d479851
1ac1d9ec-1159-11f1-9e44-4cf95d479851
1ac1da50-1159-11f1-9e44-4cf95d479851
1ac1dab4-1159-11f1-9e44-4cf95d479851
1ac1db18-1159-11f1-9e44-4cf95d479851
1ac1db72-1159-11f1-9e44-4cf95d479851
1ac1dbcc-1159-11f1-9e44-4cf95d479851

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)

5da46316-f101-8703-87ea-5ce32bd83b97
eb9e6416-f101-8703-87ea-5ce32bd83b97
536a6516-f101-8703-87ea-5ce32bd83b97
a4c26616-f101-8703-87ea-5ce32bd83b97
2dfa6716-f101-8703-87ea-5ce32bd83b97
17426816-f101-8703-87ea-5ce32bd83b97
32a46916-f101-8703-87ea-5ce32bd83b97
3dc16a16-f101-8703-87ea-5ce32bd83b97
07ac6b16-f101-8703-87ea-5ce32bd83b97
a4f96c16-f101-8703-87ea-5ce32bd83b97
630a6d16-f101-8703-87ea-5ce32bd83b97
e3cf6e16-f101-8703-87ea-5ce32bd83b97
8b5f6f16-f101-8703-87ea-5ce32bd83b97
59967016-f101-8703-87ea-5ce32bd83b97
31c17116-f101-8703-87ea-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: