UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019f8a64-f5f4-7c3a-8692-43c93e32f24e
019f8a64-f5f4-7e2e-9577-164eefa38e59
019f8a64-f5f4-7f71-bcb7-a18f66888a11
019f8a64-f5f5-7090-9390-d13585beab10
019f8a64-f5f5-71a6-8950-e96e91076233
019f8a64-f5f5-72bd-81cf-abcbc15ec3a3
019f8a64-f5f5-73d8-8ddf-55f1343deaea
019f8a64-f5f5-74ee-9432-474c4970aa13
019f8a64-f5f5-7605-a830-faa290153176
019f8a64-f5f5-771b-b300-f7dd8eead543
019f8a64-f5f5-7832-a243-14d3c4337022
019f8a64-f5f5-7948-bcbe-708d8f947de8
019f8a64-f5f5-7a5f-93b6-9b98a8663439
019f8a64-f5f5-7b7d-8142-93ee7d8654d3
019f8a64-f5f5-7c94-b160-5cf8f02abf2e

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)

1f185e01-b491-6794-ba23-4cf95d479851
1f185e01-b491-697e-ba23-4cf95d479851
1f185e01-b491-6a78-ba23-4cf95d479851
1f185e01-b491-6b54-ba23-4cf95d479851
1f185e01-b491-6c30-ba23-4cf95d479851
1f185e01-b491-6cf8-ba23-4cf95d479851
1f185e01-b491-6dca-ba23-4cf95d479851
1f185e01-b491-6e92-ba23-4cf95d479851
1f185e01-b491-6f64-ba23-4cf95d479851
1f185e01-b492-6036-ba23-4cf95d479851
1f185e01-b492-619e-ba23-4cf95d479851
1f185e01-b492-6284-ba23-4cf95d479851
1f185e01-b492-634c-ba23-4cf95d479851
1f185e01-b492-641e-ba23-4cf95d479851
1f185e01-b492-64e6-ba23-4cf95d479851

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)

1b4925cc-85e0-11f1-ba23-4cf95d479851
1b49263a-85e0-11f1-ba23-4cf95d479851
1b49269e-85e0-11f1-ba23-4cf95d479851
1b492702-85e0-11f1-ba23-4cf95d479851
1b492766-85e0-11f1-ba23-4cf95d479851
1b4927ca-85e0-11f1-ba23-4cf95d479851
1b492842-85e0-11f1-ba23-4cf95d479851
1b4928a6-85e0-11f1-ba23-4cf95d479851
1b49290a-85e0-11f1-ba23-4cf95d479851
1b492978-85e0-11f1-ba23-4cf95d479851
1b4929dc-85e0-11f1-ba23-4cf95d479851
1b492a40-85e0-11f1-ba23-4cf95d479851
1b492aa4-85e0-11f1-ba23-4cf95d479851
1b492b12-85e0-11f1-ba23-4cf95d479851
1b492b76-85e0-11f1-ba23-4cf95d479851

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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

9a153700-9403-8b0c-87ea-5ce32bd83b97
536f3800-9403-8b0c-87ea-5ce32bd83b97
4af43900-9403-8b0c-87ea-5ce32bd83b97
64dd3a00-9403-8b0c-87ea-5ce32bd83b97
b0bb3b00-9403-8b0c-87ea-5ce32bd83b97
67e83c00-9403-8b0c-87ea-5ce32bd83b97
b45a3d00-9403-8b0c-87ea-5ce32bd83b97
cb103e00-9403-8b0c-87ea-5ce32bd83b97
0c023f00-9403-8b0c-87ea-5ce32bd83b97
03374000-9403-8b0c-87ea-5ce32bd83b97
4bf24100-9403-8b0c-87ea-5ce32bd83b97
45cd4200-9403-8b0c-87ea-5ce32bd83b97
48914300-9403-8b0c-87ea-5ce32bd83b97
40a84400-9403-8b0c-87ea-5ce32bd83b97
5fb84500-9403-8b0c-87ea-5ce32bd83b97

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)

ca9a4968-2004-4b6a-aefa-6a9c9c2f1b25
36cd8c77-d3e1-4cec-b4e9-0f02713458d2
294d4e27-75f3-435e-9c13-ee8fbf7e5664
38a5b512-4666-4878-a590-43baa81a0035
6ad48178-1e41-4550-9390-31d385a5e7fb
d0d4337a-df4c-46a9-a273-0e1d6e7e97fd
c95f643f-ce70-4994-bac0-a32963df1acc
d8e95991-c4f5-4d29-a9bc-e834f170fa60
f5ec6253-abfe-45d3-a169-f6682c34aa3b
604851db-5e1e-4300-adc3-c6c8e151026d
8bf6c50e-80b6-4a7a-9b5f-6a61f6f0261f
635360c2-b6dd-4614-a69a-d3bf87b4b329
c1d34c05-13d1-45ca-b72e-18777dd578bb
5b424fa2-dd74-4f63-8f6e-ad185d8743b3
62261f13-5a73-4f91-86da-fc94ad6f6f48

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: