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)

019c017f-9108-7dfc-a47c-f7417ecc8b6a
019c017f-9108-7fb7-abd2-85229dc44438
019c017f-9109-7103-ae43-8324156d8b3e
019c017f-9109-7225-be90-103ac5456230
019c017f-9109-7344-9edc-952242c989e1
019c017f-9109-745f-ba46-c7a94f3f8a6d
019c017f-9109-7579-aa26-31ced4017cc3
019c017f-9109-7694-99ba-ed0764fca07f
019c017f-9109-77aa-aadb-027b96ac5b9c
019c017f-9109-78c5-8a1d-f9a3791b30fc
019c017f-9109-79e0-b903-10af5e26ddae
019c017f-9109-7af6-b233-fc1fbd458083
019c017f-9109-7c11-953a-449c84c2f576
019c017f-9109-7d2c-a5c0-95617f073ff5
019c017f-9109-7e46-a078-dd0138c90614

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)

1f0fbcc9-a92d-67ae-86dd-4cf95d479851
1f0fbcc9-a92d-695c-86dd-4cf95d479851
1f0fbcc9-a92d-6a42-86dd-4cf95d479851
1f0fbcc9-a92d-6b0a-86dd-4cf95d479851
1f0fbcc9-a92d-6bd2-86dd-4cf95d479851
1f0fbcc9-a92d-6c9a-86dd-4cf95d479851
1f0fbcc9-a92d-6d58-86dd-4cf95d479851
1f0fbcc9-a92d-6e20-86dd-4cf95d479851
1f0fbcc9-a92d-6ede-86dd-4cf95d479851
1f0fbcc9-a92d-6f9c-86dd-4cf95d479851
1f0fbcc9-a92e-60e6-86dd-4cf95d479851
1f0fbcc9-a92e-61b8-86dd-4cf95d479851
1f0fbcc9-a92e-6276-86dd-4cf95d479851
1f0fbcc9-a92e-6334-86dd-4cf95d479851
1f0fbcc9-a92e-63fc-86dd-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)

21fa3110-a921-4725-83ea-99e9ee2f72de
2a97a284-951d-44a0-b8ce-18d0e447b427
db0c84e7-2a06-4cbc-adc1-d4a1df23b5c0
01e451a9-244a-4cc0-b285-a7737729547f
318206e2-5982-4d51-9e5b-9d05560d30ae
c7ebe85e-6b9e-483c-bbd8-02ee74b2c982
825811d3-fa95-4a89-ab43-45893987804d
42f4fc6c-66ef-434b-884a-f3264a9f675f
6dce8d11-ccad-44ea-83b9-8a4957e4a6c5
b42c03ec-43f8-46d7-a8ba-5ad9b3bc5c5a
190e617a-e223-481f-bcf1-47f5919bd92e
46d390ab-be88-4be4-a650-afe35d2c8aea
84a36931-fafa-45bc-9ce7-a936c9ec703f
f2201994-d59c-4c6e-a83f-e0bd783825e7
789d3cdf-baa1-45f2-84f2-33b476f40bd7

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)

9a92e910-fbcc-11f0-86dd-4cf95d479851
9a92e97e-fbcc-11f0-86dd-4cf95d479851
9a92e9e2-fbcc-11f0-86dd-4cf95d479851
9a92ea46-fbcc-11f0-86dd-4cf95d479851
9a92eaa0-fbcc-11f0-86dd-4cf95d479851
9a92eb0e-fbcc-11f0-86dd-4cf95d479851
9a92eb68-fbcc-11f0-86dd-4cf95d479851
9a92ebcc-fbcc-11f0-86dd-4cf95d479851
9a92ec26-fbcc-11f0-86dd-4cf95d479851
9a92ec8a-fbcc-11f0-86dd-4cf95d479851
9a92ece4-fbcc-11f0-86dd-4cf95d479851
9a92ed3e-fbcc-11f0-86dd-4cf95d479851
9a92eda2-fbcc-11f0-86dd-4cf95d479851
9a92edfc-fbcc-11f0-86dd-4cf95d479851
9a92ee56-fbcc-11f0-86dd-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)

115f5e2b-3005-8b01-87ea-5ce32bd83b97
324e5f2b-3005-8b01-87ea-5ce32bd83b97
b167602b-3005-8b01-87ea-5ce32bd83b97
9006622b-3005-8b01-87ea-5ce32bd83b97
6c28632b-3005-8b01-87ea-5ce32bd83b97
ba81642b-3005-8b01-87ea-5ce32bd83b97
ee43652b-3005-8b01-87ea-5ce32bd83b97
dae3662b-3005-8b01-87ea-5ce32bd83b97
f4a8672b-3005-8b01-87ea-5ce32bd83b97
bb73682b-3005-8b01-87ea-5ce32bd83b97
0c26692b-3005-8b01-87ea-5ce32bd83b97
43db6a2b-3005-8b01-87ea-5ce32bd83b97
dd636b2b-3005-8b01-87ea-5ce32bd83b97
39b86c2b-3005-8b01-87ea-5ce32bd83b97
ee5d6d2b-3005-8b01-87ea-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: