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)

019f597c-2cc9-7579-9962-5834acace16c
019f597c-2cc9-776d-b2e5-e6ee2401a79d
019f597c-2cc9-78d1-87c1-01f08a04a159
019f597c-2cc9-7a15-837a-e83390e98d1a
019f597c-2cc9-7b50-8394-9e6b108ec1a7
019f597c-2cc9-7c8c-a6bd-2a1a14eeebe5
019f597c-2cc9-7dc3-a32c-1cdffc264c13
019f597c-2cc9-7efe-908f-098c1f389561
019f597c-2cca-703a-b7d9-8eb00a66217f
019f597c-2cca-7175-82c7-072848dfb3bb
019f597c-2cca-72b1-b84a-a0d632701826
019f597c-2cca-73e8-9b28-2ec395a6da0e
019f597c-2cca-751f-9996-6dc9780ab155
019f597c-2cca-765b-9696-1f52ea98a734
019f597c-2cca-779a-8946-6e18e2e0edef

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)

1f17e699-616e-6b46-b16f-4cf95d479851
1f17e699-616e-6dc6-b16f-4cf95d479851
1f17e699-616e-6f2e-b16f-4cf95d479851
1f17e699-616f-608c-b16f-4cf95d479851
1f17e699-616f-61e0-b16f-4cf95d479851
1f17e699-616f-632a-b16f-4cf95d479851
1f17e699-616f-647e-b16f-4cf95d479851
1f17e699-616f-65c8-b16f-4cf95d479851
1f17e699-616f-6712-b16f-4cf95d479851
1f17e699-616f-685c-b16f-4cf95d479851
1f17e699-616f-6a64-b16f-4cf95d479851
1f17e699-616f-6bb8-b16f-4cf95d479851
1f17e699-616f-6d0c-b16f-4cf95d479851
1f17e699-616f-6e56-b16f-4cf95d479851
1f17e699-616f-6fa0-b16f-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)

96170108-7e69-11f1-b16f-4cf95d479851
9617019e-7e69-11f1-b16f-4cf95d479851
96170234-7e69-11f1-b16f-4cf95d479851
961702ca-7e69-11f1-b16f-4cf95d479851
96170360-7e69-11f1-b16f-4cf95d479851
961703f6-7e69-11f1-b16f-4cf95d479851
96170482-7e69-11f1-b16f-4cf95d479851
96170518-7e69-11f1-b16f-4cf95d479851
961705a4-7e69-11f1-b16f-4cf95d479851
9617063a-7e69-11f1-b16f-4cf95d479851
961706d0-7e69-11f1-b16f-4cf95d479851
96170766-7e69-11f1-b16f-4cf95d479851
961707f2-7e69-11f1-b16f-4cf95d479851
96170888-7e69-11f1-b16f-4cf95d479851
96170914-7e69-11f1-b16f-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)

b600fe39-c700-820c-87ea-5ce32bd83b97
c850ff39-c700-820c-87ea-5ce32bd83b97
cc40013a-c700-820c-87ea-5ce32bd83b97
1fa2023a-c700-820c-87ea-5ce32bd83b97
90ba033a-c700-820c-87ea-5ce32bd83b97
d3bf043a-c700-820c-87ea-5ce32bd83b97
582c053a-c700-820c-87ea-5ce32bd83b97
c263063a-c700-820c-87ea-5ce32bd83b97
5ec0073a-c700-820c-87ea-5ce32bd83b97
cbf7083a-c700-820c-87ea-5ce32bd83b97
c1fb093a-c700-820c-87ea-5ce32bd83b97
eafb0a3a-c700-820c-87ea-5ce32bd83b97
94400b3a-c700-820c-87ea-5ce32bd83b97
2f8b0c3a-c700-820c-87ea-5ce32bd83b97
417a0d3a-c700-820c-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)

0a4c2103-f734-48b1-9125-2854ae55fbee
8880d238-69e5-4b9a-b405-e5b6c6da089f
7dada423-eb5b-40cc-9242-eb2460b122e9
79b0f835-ba58-41b0-a9b3-4793ae6550c8
c7ea1b88-eae1-42b1-83c8-9ae34d67f2ed
19a09509-13b2-4faa-acff-008dec9813ac
8891dbfd-c828-403a-a6bd-0b86fd8c1c7c
e626c424-1554-4d8d-bf4e-f5620c56f0d2
d2fa0f03-19aa-40b5-a708-5ac725bf2528
79c75aa4-f54f-4f1d-a21a-4193a03dc994
6fed11b9-1184-4b49-9d37-d8f6bfc04b8b
f071e3c4-d07c-43bd-b5bd-92a4973b089c
c8b75922-03bb-48f3-972a-5d12b120e961
84acf00e-7641-47db-ac13-95185c2984d6
e50d7a8c-f5cd-4e61-b9d2-0ce5676a055f

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: