UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019f6a62-0a35-798e-8ab4-ddd27b5c65b5
019f6a62-0a35-7b48-a666-2c88fd2050f6
019f6a62-0a35-7cbd-b1e8-bfcb5405b925
019f6a62-0a35-7de8-a287-baba7be180bf
019f6a62-0a35-7f2c-88f4-916f7cb9e566
019f6a62-0a36-7057-9abd-6231e86bd06c
019f6a62-0a36-7192-8488-1d239499386f
019f6a62-0a36-72bd-bebe-0063d4b94bcf
019f6a62-0a36-7405-8b73-bb93b143e92a
019f6a62-0a36-7540-8676-ae4f44b1b93e
019f6a62-0a36-767f-95a3-6dd12ab0c841
019f6a62-0a36-77f0-99f9-67137b805223
019f6a62-0a36-7934-89d8-098858c0ea77
019f6a62-0a36-7a7b-ab1d-d3e5285c709d
019f6a62-0a36-7ba2-8351-9dea61e169a4

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)

1f180fda-9303-6dea-88c7-4cf95d479851
1f180fda-9303-6f8e-88c7-4cf95d479851
1f180fda-9304-606a-88c7-4cf95d479851
1f180fda-9304-61d2-88c7-4cf95d479851
1f180fda-9304-6344-88c7-4cf95d479851
1f180fda-9304-64b6-88c7-4cf95d479851
1f180fda-9304-6614-88c7-4cf95d479851
1f180fda-9304-66f0-88c7-4cf95d479851
1f180fda-9304-67b8-88c7-4cf95d479851
1f180fda-9304-6880-88c7-4cf95d479851
1f180fda-9304-69ca-88c7-4cf95d479851
1f180fda-9304-6b32-88c7-4cf95d479851
1f180fda-9304-6cae-88c7-4cf95d479851
1f180fda-9304-6d9e-88c7-4cf95d479851
1f180fda-9304-6e5c-88c7-4cf95d479851

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)

a9304f2e-80fd-11f1-88c7-4cf95d479851
a9304f9c-80fd-11f1-88c7-4cf95d479851
a9304ff6-80fd-11f1-88c7-4cf95d479851
a930505a-80fd-11f1-88c7-4cf95d479851
a93050b4-80fd-11f1-88c7-4cf95d479851
a9305118-80fd-11f1-88c7-4cf95d479851
a9305186-80fd-11f1-88c7-4cf95d479851
a93051ea-80fd-11f1-88c7-4cf95d479851
a9305244-80fd-11f1-88c7-4cf95d479851
a93052a8-80fd-11f1-88c7-4cf95d479851
a9305302-80fd-11f1-88c7-4cf95d479851
a930535c-80fd-11f1-88c7-4cf95d479851
a93053ca-80fd-11f1-88c7-4cf95d479851
a930542e-80fd-11f1-88c7-4cf95d479851
a9305492-80fd-11f1-88c7-4cf95d479851

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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

fd88e039-5c02-850c-87ea-5ce32bd83b97
e2f1e139-5c02-850c-87ea-5ce32bd83b97
4ad3e239-5c02-850c-87ea-5ce32bd83b97
dd90e339-5c02-850c-87ea-5ce32bd83b97
14e5e439-5c02-850c-87ea-5ce32bd83b97
fdbee539-5c02-850c-87ea-5ce32bd83b97
84e5e639-5c02-850c-87ea-5ce32bd83b97
bbf0e839-5c02-850c-87ea-5ce32bd83b97
38b5e939-5c02-850c-87ea-5ce32bd83b97
bae5ea39-5c02-850c-87ea-5ce32bd83b97
1355eb39-5c02-850c-87ea-5ce32bd83b97
280cec39-5c02-850c-87ea-5ce32bd83b97
d7aaed39-5c02-850c-87ea-5ce32bd83b97
508aee39-5c02-850c-87ea-5ce32bd83b97
8bc1ef39-5c02-850c-87ea-5ce32bd83b97

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)

8f65e506-6b6a-4ace-9a79-c39f75c00b0c
e803615a-e757-4429-ad3e-2c29f3b3bc91
9b91a8f5-a863-43ed-bef0-95f8425c39f4
7607b02d-21e1-4425-a2cc-e1795b1890a7
4db1e0a5-84cd-41e2-8021-b84c29b87e6f
e4c9f4a6-00b0-4dbd-9787-2a841b1e4d8e
0c3d19e3-48ba-42a7-9f62-52fe4ad4e2cc
6daf7f4b-c9fd-4f4c-b30c-3e0d7aa7a68e
a9ad355c-4a40-4e2f-9e1c-3429bb4716a9
c0b42aa6-f327-451b-86ff-52eeb099a658
180a870d-5074-4d9a-a533-5b6d079a9c7c
d90dfbf9-3ad8-4eea-a73b-e5da0d90f181
7dbfc411-8a30-4991-add2-40c09c1f0cdb
7c4d41ff-9edc-4bae-9485-f15137d462bf
bfa86a04-c6c6-4799-85da-1dd9a90c9545

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: