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)

019bd60a-9c1d-71cb-8061-f0a0ab5038cf
019bd60a-9c1d-7375-8b2b-27cc5d50ac83
019bd60a-9c1d-74b5-98f4-aacbc7645c50
019bd60a-9c1d-75d8-8ebd-5c21d1779a31
019bd60a-9c1d-76f2-be6c-2145fab912f2
019bd60a-9c1d-7811-82c8-4648c47136a6
019bd60a-9c1d-792c-821d-899e794d3e21
019bd60a-9c1d-7a4e-ae3a-5f6c21bae5a2
019bd60a-9c1d-7b65-b57e-3ed5eb2fcb29
019bd60a-9c1d-7c7f-a6e5-d95d16551971
019bd60a-9c1d-7d9a-9ba2-1cc98296429e
019bd60a-9c1d-7e7b-aacb-3ee98890d364
019bd60a-9c1d-7f9a-ac70-0f006cdcc8c2
019bd60a-9c1e-70b5-81c0-ec4a9dfe4cc7
019bd60a-9c1e-71cf-a9b3-c853a650b2ad

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)

1f0f52b1-1f39-6c50-999e-4cf95d479851
1f0f52b1-1f39-6e26-999e-4cf95d479851
1f0f52b1-1f39-6f0c-999e-4cf95d479851
1f0f52b1-1f39-6fe8-999e-4cf95d479851
1f0f52b1-1f3a-60ba-999e-4cf95d479851
1f0f52b1-1f3a-618c-999e-4cf95d479851
1f0f52b1-1f3a-6254-999e-4cf95d479851
1f0f52b1-1f3a-631c-999e-4cf95d479851
1f0f52b1-1f3a-63e4-999e-4cf95d479851
1f0f52b1-1f3a-64ac-999e-4cf95d479851
1f0f52b1-1f3a-65f6-999e-4cf95d479851
1f0f52b1-1f3a-66c8-999e-4cf95d479851
1f0f52b1-1f3a-6790-999e-4cf95d479851
1f0f52b1-1f3a-684e-999e-4cf95d479851
1f0f52b1-1f3a-6916-999e-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)

46ce4b59-d2a8-4195-baed-709c28ae2b5c
7e23c896-b240-4111-bf17-dd5a9708ac6c
f1962fc7-3ad9-4511-8c48-0afc6499172a
48233fe2-c213-4a4f-9bf4-7182c6f1d5a1
d4b8fccd-489a-4316-8a51-6a4ea90c4348
b76828f0-18c8-4bde-b3ed-ed94451e253f
2168633a-e34b-4742-9708-ab703481d518
6face159-bf41-4558-9c50-23711d6e4298
d565912d-0785-4afd-918b-a4168167c8bc
46e24c76-832e-4e5d-b64f-a09da6d89cb0
cc088ce4-8e52-472d-8bc6-24610a31587c
f8c3bbfb-c961-4afa-9b3b-72663d7eae05
40bc0347-e962-452f-9716-6a243c68ca66
587a9254-7da4-44dd-89c4-e430b52abd1e
e8042387-737e-4ffa-a876-361f241aaa77

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)

11f3ae48-f52b-11f0-999e-4cf95d479851
11f3aeb6-f52b-11f0-999e-4cf95d479851
11f3af24-f52b-11f0-999e-4cf95d479851
11f3af88-f52b-11f0-999e-4cf95d479851
11f3afe2-f52b-11f0-999e-4cf95d479851
11f3b046-f52b-11f0-999e-4cf95d479851
11f3b0a0-f52b-11f0-999e-4cf95d479851
11f3b104-f52b-11f0-999e-4cf95d479851
11f3b168-f52b-11f0-999e-4cf95d479851
11f3b1d6-f52b-11f0-999e-4cf95d479851
11f3b244-f52b-11f0-999e-4cf95d479851
11f3b2a8-f52b-11f0-999e-4cf95d479851
11f3b316-f52b-11f0-999e-4cf95d479851
11f3b37a-f52b-11f0-999e-4cf95d479851
11f3b3de-f52b-11f0-999e-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)

47d73512-b902-8301-87ea-5ce32bd83b97
0f603612-b902-8301-87ea-5ce32bd83b97
ac033712-b902-8301-87ea-5ce32bd83b97
ee323812-b902-8301-87ea-5ce32bd83b97
9dc73912-b902-8301-87ea-5ce32bd83b97
1e2a3a12-b902-8301-87ea-5ce32bd83b97
61203b12-b902-8301-87ea-5ce32bd83b97
ed653c12-b902-8301-87ea-5ce32bd83b97
bdba3d12-b902-8301-87ea-5ce32bd83b97
ed7f3e12-b902-8301-87ea-5ce32bd83b97
e9f43f12-b902-8301-87ea-5ce32bd83b97
9e2e4012-b902-8301-87ea-5ce32bd83b97
9d0b4112-b902-8301-87ea-5ce32bd83b97
91c04212-b902-8301-87ea-5ce32bd83b97
3a684312-b902-8301-87ea-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: