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)

019bfc30-8fee-7313-87a1-cc0f651cdffb
019bfc30-8fee-74c9-be86-6915caca6820
019bfc30-8fee-7609-9fcc-268b15f68d0b
019bfc30-8fee-7727-99f8-250fe3a158a2
019bfc30-8fee-783e-8f44-d3f511e122cc
019bfc30-8fee-7959-b293-50987c029667
019bfc30-8fee-7a6f-86f9-50bfb31a070f
019bfc30-8fee-7b86-b8e8-e7cc8b98c5fb
019bfc30-8fee-7c98-8e6a-822384244ca0
019bfc30-8fee-7daf-b129-01045879cbe7
019bfc30-8fee-7ec5-9755-abea1838acb8
019bfc30-8fee-7fdc-962d-cd338e1ee5f9
019bfc30-8fef-70ee-92de-b0f35e3c2089
019bfc30-8fef-7209-a8e5-f2689742a5a7
019bfc30-8fef-731f-b353-2d72b4d2e3f2

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)

1f0fafd3-c77b-64f2-80e9-4cf95d479851
1f0fafd3-c77b-66c8-80e9-4cf95d479851
1f0fafd3-c77b-67ae-80e9-4cf95d479851
1f0fafd3-c77b-6902-80e9-4cf95d479851
1f0fafd3-c77b-6a42-80e9-4cf95d479851
1f0fafd3-c77b-6b14-80e9-4cf95d479851
1f0fafd3-c77b-6bdc-80e9-4cf95d479851
1f0fafd3-c77b-6c9a-80e9-4cf95d479851
1f0fafd3-c77b-6d58-80e9-4cf95d479851
1f0fafd3-c77b-6e16-80e9-4cf95d479851
1f0fafd3-c77b-6f60-80e9-4cf95d479851
1f0fafd3-c77c-6032-80e9-4cf95d479851
1f0fafd3-c77c-60f0-80e9-4cf95d479851
1f0fafd3-c77c-61ae-80e9-4cf95d479851
1f0fafd3-c77c-626c-80e9-4cf95d479851

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)

bd0a4baa-6429-4b15-853c-8892caa5388f
796bcf74-88a8-4baa-bc52-9dc3c423a931
c8243a10-dc4b-4d45-bbdc-4c2bc8eeea07
64096d71-095f-4325-943e-2bd256456c31
67f442cd-602f-4d14-8415-e2aca1d427d4
97012327-0ad2-4de4-a72c-cf0757753e23
f228f07e-56c9-4ef4-829f-4ce9354c3f34
26bec7b7-b2d2-455a-8e87-8b4e85a0aa04
a539419a-d3ca-4492-91df-66da0c302bcf
d9e06ba8-6f5b-476f-bf75-37d87cd4175a
f9d14f90-270c-41d5-b2ea-1b48d8f0afb6
ffdde775-d829-4aa8-82fc-e65da1b8b9e4
b25190a9-478a-4db9-97ef-0537a5a6467d
8323facb-0f17-4019-85b9-04704fc7aea9
8423c89a-f475-4d4d-a128-ce3fcd541e76

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)

3c77c78a-fafd-11f0-80e9-4cf95d479851
3c77c7ee-fafd-11f0-80e9-4cf95d479851
3c77c852-fafd-11f0-80e9-4cf95d479851
3c77c8b6-fafd-11f0-80e9-4cf95d479851
3c77c910-fafd-11f0-80e9-4cf95d479851
3c77c97e-fafd-11f0-80e9-4cf95d479851
3c77c9e2-fafd-11f0-80e9-4cf95d479851
3c77ca46-fafd-11f0-80e9-4cf95d479851
3c77cab4-fafd-11f0-80e9-4cf95d479851
3c77cb22-fafd-11f0-80e9-4cf95d479851
3c77cb86-fafd-11f0-80e9-4cf95d479851
3c77cbea-fafd-11f0-80e9-4cf95d479851
3c77cc44-fafd-11f0-80e9-4cf95d479851
3c77ccb2-fafd-11f0-80e9-4cf95d479851
3c77cd16-fafd-11f0-80e9-4cf95d479851

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)

323ba913-0405-8a01-87ea-5ce32bd83b97
99beab13-0405-8a01-87ea-5ce32bd83b97
1c0eac13-0405-8a01-87ea-5ce32bd83b97
6c23ad13-0405-8a01-87ea-5ce32bd83b97
6e76ae13-0405-8a01-87ea-5ce32bd83b97
d1d5af13-0405-8a01-87ea-5ce32bd83b97
4ba4b013-0405-8a01-87ea-5ce32bd83b97
5089b113-0405-8a01-87ea-5ce32bd83b97
49bbb213-0405-8a01-87ea-5ce32bd83b97
bfb5b313-0405-8a01-87ea-5ce32bd83b97
ee44b413-0405-8a01-87ea-5ce32bd83b97
9e90b513-0405-8a01-87ea-5ce32bd83b97
bbafb613-0405-8a01-87ea-5ce32bd83b97
eb65b713-0405-8a01-87ea-5ce32bd83b97
e4c3b813-0405-8a01-87ea-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: