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)

019b2ad9-b300-78da-8c2b-8a6d1cacaa78
019b2ad9-b300-7a63-8ae8-46214ee9281a
019b2ad9-b300-7ba6-8e01-52cf13404ade
019b2ad9-b300-7cc9-91c3-893a82bbcf49
019b2ad9-b300-7de4-b204-18c59688aca5
019b2ad9-b300-7efa-83a6-c60997accfea
019b2ad9-b301-7015-8974-18b783cfc27a
019b2ad9-b301-7130-a3b9-c264edec71c0
019b2ad9-b301-724a-9b2c-6178d60b2004
019b2ad9-b301-7365-8222-3cdbf0b045ca
019b2ad9-b301-747b-8268-6cb47790a615
019b2ad9-b301-7596-af00-43f0796787c1
019b2ad9-b301-76ad-8b19-d64e53031068
019b2ad9-b301-77cb-b5e4-270fcd6a6586
019b2ad9-b301-78e6-8483-fcb1a2155f40

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)

1f0db0be-b61b-609c-ab15-4cf95d479851
1f0db0be-b61b-6222-ab15-4cf95d479851
1f0db0be-b61b-6312-ab15-4cf95d479851
1f0db0be-b61b-63da-ab15-4cf95d479851
1f0db0be-b61b-64a2-ab15-4cf95d479851
1f0db0be-b61b-656a-ab15-4cf95d479851
1f0db0be-b61b-6628-ab15-4cf95d479851
1f0db0be-b61b-66e6-ab15-4cf95d479851
1f0db0be-b61b-67ae-ab15-4cf95d479851
1f0db0be-b61b-686c-ab15-4cf95d479851
1f0db0be-b61b-69a2-ab15-4cf95d479851
1f0db0be-b61b-6a6a-ab15-4cf95d479851
1f0db0be-b61b-6b32-ab15-4cf95d479851
1f0db0be-b61b-6bf0-ab15-4cf95d479851
1f0db0be-b61b-6cae-ab15-4cf95d479851

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)

60cd2412-6338-4eeb-b4a7-8dc9853f7d6c
87bb65b5-d2ac-4df7-baaf-efeede83288d
3f5971bc-d651-4831-856a-4fc9bd882cd0
549b30a4-0934-4bba-aa6f-4f0ea6af7591
42a78690-9c58-482b-95fa-6dbadcf65681
fe711d46-fe32-4bf0-afdc-acb7618d79a1
c587d7be-31e7-4294-a336-a6274b5fa64c
7358038e-84ac-4937-be20-0c8352dfd8c9
663f62ef-c9da-41f8-b84d-b25108a8473a
def7eb41-3b90-4b39-8378-695e64bc17c0
98483d6d-bcae-4074-974b-0cc6af6eb041
ecabaa61-cac9-43a7-9a04-0fd062c178e2
a85dc195-297a-4f0f-90bf-e678fd3bcca6
4372424d-54be-4383-80fa-962318fe2668
90a5f99e-748c-4080-af2d-a2ceddf4ca15

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)

eb61c1c2-db0b-11f0-ab15-4cf95d479851
eb61c230-db0b-11f0-ab15-4cf95d479851
eb61c28a-db0b-11f0-ab15-4cf95d479851
eb61c2f8-db0b-11f0-ab15-4cf95d479851
eb61c35c-db0b-11f0-ab15-4cf95d479851
eb61c3ca-db0b-11f0-ab15-4cf95d479851
eb61c424-db0b-11f0-ab15-4cf95d479851
eb61c488-db0b-11f0-ab15-4cf95d479851
eb61c4e2-db0b-11f0-ab15-4cf95d479851
eb61c550-db0b-11f0-ab15-4cf95d479851
eb61c5aa-db0b-11f0-ab15-4cf95d479851
eb61c604-db0b-11f0-ab15-4cf95d479851
eb61c668-db0b-11f0-ab15-4cf95d479851
eb61c6c2-db0b-11f0-ab15-4cf95d479851
eb61c71c-db0b-11f0-ab15-4cf95d479851

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)

4863dd30-5c01-8f15-87e9-5ce32bd83b97
8352de30-5c01-8f15-87e9-5ce32bd83b97
d436df30-5c01-8f15-87e9-5ce32bd83b97
df68e030-5c01-8f15-87e9-5ce32bd83b97
8c7fe130-5c01-8f15-87e9-5ce32bd83b97
5589e230-5c01-8f15-87e9-5ce32bd83b97
be78e330-5c01-8f15-87e9-5ce32bd83b97
af39e430-5c01-8f15-87e9-5ce32bd83b97
4b48e530-5c01-8f15-87e9-5ce32bd83b97
b340e630-5c01-8f15-87e9-5ce32bd83b97
e2f4e830-5c01-8f15-87e9-5ce32bd83b97
0c47e930-5c01-8f15-87e9-5ce32bd83b97
ef7bea30-5c01-8f15-87e9-5ce32bd83b97
1a07eb30-5c01-8f15-87e9-5ce32bd83b97
2badec30-5c01-8f15-87e9-5ce32bd83b97

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: