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)

019cb765-1615-7792-9be3-0c6ea3ec7c41
019cb765-1615-7971-9d2b-d84591a10a11
019cb765-1615-7af6-be78-74d3f97f62b0
019cb765-1615-7c5f-96e6-4e902f3dce75
019cb765-1615-7dbb-9ac3-9060468c9b70
019cb765-1615-7f17-87af-a248789658a0
019cb765-1616-7077-af49-31f22da5d76c
019cb765-1616-71cb-b91f-b11eb5f417ca
019cb765-1616-731b-914a-c79b56930aec
019cb765-1616-7467-bec8-bb279268bd12
019cb765-1616-75b3-aa73-69ee1485b2c9
019cb765-1616-7707-8d65-d40c99360e23
019cb765-1616-7857-a718-9b0528030ce5
019cb765-1616-79a6-8dbd-7c819572b423
019cb765-1616-7afa-a5a9-566bd0cdf45d

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)

1f1178df-0301-6af0-b4c6-4cf95d479851
1f1178df-0301-6d20-b4c6-4cf95d479851
1f1178df-0301-6e9c-b4c6-4cf95d479851
1f1178df-0301-6ff0-b4c6-4cf95d479851
1f1178df-0302-6144-b4c6-4cf95d479851
1f1178df-0302-6284-b4c6-4cf95d479851
1f1178df-0302-63ce-b4c6-4cf95d479851
1f1178df-0302-650e-b4c6-4cf95d479851
1f1178df-0302-6658-b4c6-4cf95d479851
1f1178df-0302-6798-b4c6-4cf95d479851
1f1178df-0302-6996-b4c6-4cf95d479851
1f1178df-0302-6ae0-b4c6-4cf95d479851
1f1178df-0302-6c34-b4c6-4cf95d479851
1f1178df-0302-6d92-b4c6-4cf95d479851
1f1178df-0302-6edc-b4c6-4cf95d479851

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)

a69a8ee3-e284-4383-8d31-15fb9d7e550d
fe837033-0c2f-431d-bf51-153d8efd32b6
1936e438-f734-4544-8970-fed4aae561f6
6bb3f85d-f9c0-4627-b4a8-faa1d75df76b
b8e1303c-60f1-4654-b212-bf92afe7faa3
51ec4d05-0ab1-4c4b-a91a-b6fed50c46cf
c178c828-8dd5-4012-a439-58b708772a62
9e3b0ebf-9dc6-48bc-880f-f70e83e19199
85b8d470-66f9-4ac6-87f4-b34de73db663
3b092634-8550-46ea-9229-eff0530bafed
da9500a2-f063-481e-9dc2-17c3852fb92b
2db61dc4-9883-48b6-9fbf-6cd365fa601a
cc135f7b-a1fe-4263-b3e6-244961b432ac
d04d442a-06e2-49f0-88d3-0d6ad08672ad
24be5482-03e4-4ba6-aad8-3392ef849e60

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)

f03036ac-178d-11f1-b4c6-4cf95d479851
f030374c-178d-11f1-b4c6-4cf95d479851
f03037e2-178d-11f1-b4c6-4cf95d479851
f0303878-178d-11f1-b4c6-4cf95d479851
f0303904-178d-11f1-b4c6-4cf95d479851
f030399a-178d-11f1-b4c6-4cf95d479851
f0303a30-178d-11f1-b4c6-4cf95d479851
f0303ac6-178d-11f1-b4c6-4cf95d479851
f0303b66-178d-11f1-b4c6-4cf95d479851
f0303bfc-178d-11f1-b4c6-4cf95d479851
f0303c9c-178d-11f1-b4c6-4cf95d479851
f0303d3c-178d-11f1-b4c6-4cf95d479851
f0303dd2-178d-11f1-b4c6-4cf95d479851
f0303e68-178d-11f1-b4c6-4cf95d479851
f0303f08-178d-11f1-b4c6-4cf95d479851

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)

afa84529-5e01-8f03-87ea-5ce32bd83b97
41e94629-5e01-8f03-87ea-5ce32bd83b97
df4c4729-5e01-8f03-87ea-5ce32bd83b97
f8284829-5e01-8f03-87ea-5ce32bd83b97
ec834a29-5e01-8f03-87ea-5ce32bd83b97
00244b29-5e01-8f03-87ea-5ce32bd83b97
75d04c29-5e01-8f03-87ea-5ce32bd83b97
dbbf4d29-5e01-8f03-87ea-5ce32bd83b97
43a64e29-5e01-8f03-87ea-5ce32bd83b97
80784f29-5e01-8f03-87ea-5ce32bd83b97
c1315029-5e01-8f03-87ea-5ce32bd83b97
25365129-5e01-8f03-87ea-5ce32bd83b97
e16c5229-5e01-8f03-87ea-5ce32bd83b97
f06f5329-5e01-8f03-87ea-5ce32bd83b97
cc4a5429-5e01-8f03-87ea-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: