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)

019cee75-0f6c-7ed1-a2da-20f08c9938af
019cee75-0f6d-7090-bc3c-94b28cd68acc
019cee75-0f6d-71d3-b988-c0027f363afd
019cee75-0f6d-72f6-bfaf-caf19b3efb30
019cee75-0f6d-7411-897e-50a60b96bb7e
019cee75-0f6d-752c-8f03-6f74438c6333
019cee75-0f6d-7646-9d5c-0b9c46d2b82b
019cee75-0f6d-7761-9420-3aa44936ca2e
019cee75-0f6d-787b-bb86-2b5c9ab5dc83
019cee75-0f6d-7996-b70e-cdf586f5aa61
019cee75-0f6d-7ab1-a513-be0eab0b1e0b
019cee75-0f6d-7bcb-845e-f21d3e3f8c4c
019cee75-0f6d-7ce6-9f8c-1ab6894d9ff4
019cee75-0f6d-7e00-bcd6-44ef1d79ac7e
019cee75-0f6d-7f1b-ab68-adb1253af1e2

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)

1f11ff4d-02bf-6c96-be39-4cf95d479851
1f11ff4d-02bf-6e4e-be39-4cf95d479851
1f11ff4d-02bf-6f3e-be39-4cf95d479851
1f11ff4d-02c0-6010-be39-4cf95d479851
1f11ff4d-02c0-60d8-be39-4cf95d479851
1f11ff4d-02c0-6196-be39-4cf95d479851
1f11ff4d-02c0-625e-be39-4cf95d479851
1f11ff4d-02c0-634e-be39-4cf95d479851
1f11ff4d-02c0-64ac-be39-4cf95d479851
1f11ff4d-02c0-661e-be39-4cf95d479851
1f11ff4d-02c0-6844-be39-4cf95d479851
1f11ff4d-02c0-69ca-be39-4cf95d479851
1f11ff4d-02c0-6b46-be39-4cf95d479851
1f11ff4d-02c0-6ca4-be39-4cf95d479851
1f11ff4d-02c0-6e0c-be39-4cf95d479851

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)

3d79e9ca-ab70-451f-a94d-a1a45d000ecc
04250de1-54d8-401e-b138-0a9f2760ce97
cd6e20c7-9e92-4e7b-bc91-047f78075926
f64d34d2-99af-4558-8779-7f589843533b
a79eef16-fd23-4201-a629-595dd67072b7
ba8ebf98-d9f2-40b1-a6c0-baf154bcb30c
e83a792a-79bf-48a4-adc2-66222c7b4679
f2669928-2704-483f-b9a5-e195e1edbf39
9dc2e6aa-98a7-4edc-85bd-8e8ec6339270
1795eb39-ad51-44bd-bea2-b87579d4aea9
6cb0de0c-6a02-4e31-81dc-0dd6ad29b894
7f3265d7-0225-46c2-8ef1-fb7e51007d92
ae42b1a2-b56a-42ec-9b08-0899d04458e9
ff5b7574-0e5b-40d4-bb29-6f662fdafd26
baad56ca-c4fd-4adf-a942-71b3990665a7

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)

d02c156e-1ff4-11f1-be39-4cf95d479851
d02c1622-1ff4-11f1-be39-4cf95d479851
d02c16d6-1ff4-11f1-be39-4cf95d479851
d02c1776-1ff4-11f1-be39-4cf95d479851
d02c182a-1ff4-11f1-be39-4cf95d479851
d02c18a2-1ff4-11f1-be39-4cf95d479851
d02c1910-1ff4-11f1-be39-4cf95d479851
d02c196a-1ff4-11f1-be39-4cf95d479851
d02c19ce-1ff4-11f1-be39-4cf95d479851
d02c1a32-1ff4-11f1-be39-4cf95d479851
d02c1a96-1ff4-11f1-be39-4cf95d479851
d02c1b9a-1ff4-11f1-be39-4cf95d479851
d02c1c08-1ff4-11f1-be39-4cf95d479851
d02c1c6c-1ff4-11f1-be39-4cf95d479851
d02c1cd0-1ff4-11f1-be39-4cf95d479851

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)

8bff060f-4305-8904-87ea-5ce32bd83b97
19bc070f-4305-8904-87ea-5ce32bd83b97
0232080f-4305-8904-87ea-5ce32bd83b97
a23a090f-4305-8904-87ea-5ce32bd83b97
1c2b0a0f-4305-8904-87ea-5ce32bd83b97
6f650b0f-4305-8904-87ea-5ce32bd83b97
b5a60c0f-4305-8904-87ea-5ce32bd83b97
1c960d0f-4305-8904-87ea-5ce32bd83b97
93390e0f-4305-8904-87ea-5ce32bd83b97
d6bf0f0f-4305-8904-87ea-5ce32bd83b97
13d8100f-4305-8904-87ea-5ce32bd83b97
c940110f-4305-8904-87ea-5ce32bd83b97
bb7d120f-4305-8904-87ea-5ce32bd83b97
0f8c130f-4305-8904-87ea-5ce32bd83b97
dd8d140f-4305-8904-87ea-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: