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)

019ff833-6b5f-7b27-8cb4-7d793ffaeed7
019ff833-6b5f-7cbd-8d1e-c1674209e9bc
019ff833-6b5f-7dfc-aeab-77f57a125401
019ff833-6b5f-7f1b-8e2c-3f664e5b0f51
019ff833-6b60-7032-b039-c46cc1f5186f
019ff833-6b60-7148-8c94-dd87ce3e19a3
019ff833-6b60-725f-ba5b-61f2f284afb3
019ff833-6b60-7375-ba4c-37e30a4c762b
019ff833-6b60-748c-bea9-6e131f5aac66
019ff833-6b60-75a2-bb5f-187157402742
019ff833-6b60-76b9-bb6d-ecca33eb9421
019ff833-6b60-77d3-8c12-f9dd2809d276
019ff833-6b60-78ea-b5e9-139605b75fca
019ff833-6b60-7a09-a793-81488c3bc786
019ff833-6b60-7b1f-90b3-4b2b8c1e63c2

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)

1f196a16-c13b-6504-8956-4cf95d479851
1f196a16-c13b-669e-8956-4cf95d479851
1f196a16-c13b-6784-8956-4cf95d479851
1f196a16-c13b-684c-8956-4cf95d479851
1f196a16-c13b-690a-8956-4cf95d479851
1f196a16-c13b-69c8-8956-4cf95d479851
1f196a16-c13b-6a90-8956-4cf95d479851
1f196a16-c13b-6b4e-8956-4cf95d479851
1f196a16-c13b-6c0c-8956-4cf95d479851
1f196a16-c13b-6cc0-8956-4cf95d479851
1f196a16-c13b-6e14-8956-4cf95d479851
1f196a16-c13b-6ee6-8956-4cf95d479851
1f196a16-c13b-6fa4-8956-4cf95d479851
1f196a16-c13c-6062-8956-4cf95d479851
1f196a16-c13c-6120-8956-4cf95d479851

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)

6c13c1f2-96a1-11f1-8956-4cf95d479851
6c13c256-96a1-11f1-8956-4cf95d479851
6c13c2ba-96a1-11f1-8956-4cf95d479851
6c13c314-96a1-11f1-8956-4cf95d479851
6c13c36e-96a1-11f1-8956-4cf95d479851
6c13c3d2-96a1-11f1-8956-4cf95d479851
6c13c42c-96a1-11f1-8956-4cf95d479851
6c13c490-96a1-11f1-8956-4cf95d479851
6c13c4ea-96a1-11f1-8956-4cf95d479851
6c13c54e-96a1-11f1-8956-4cf95d479851
6c13c5b2-96a1-11f1-8956-4cf95d479851
6c13c616-96a1-11f1-8956-4cf95d479851
6c13c684-96a1-11f1-8956-4cf95d479851
6c13c6e8-96a1-11f1-8956-4cf95d479851
6c13c74c-96a1-11f1-8956-4cf95d479851

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)

82dc3b07-6405-800e-87ea-5ce32bd83b97
45a13c07-6405-800e-87ea-5ce32bd83b97
d7c63e07-6405-800e-87ea-5ce32bd83b97
cd603f07-6405-800e-87ea-5ce32bd83b97
80ea4007-6405-800e-87ea-5ce32bd83b97
a69a4107-6405-800e-87ea-5ce32bd83b97
da414207-6405-800e-87ea-5ce32bd83b97
40724307-6405-800e-87ea-5ce32bd83b97
ea7c4407-6405-800e-87ea-5ce32bd83b97
57784507-6405-800e-87ea-5ce32bd83b97
e3864607-6405-800e-87ea-5ce32bd83b97
eff94707-6405-800e-87ea-5ce32bd83b97
e98e4807-6405-800e-87ea-5ce32bd83b97
14994907-6405-800e-87ea-5ce32bd83b97
672d4a07-6405-800e-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)

87260c5e-2ef9-47f5-a9a6-8ad33e9503a9
b9b73128-274d-4a9c-88cd-94d66207ce3f
8fe56874-15dd-42c2-9cfb-b58c3a9decae
352726dc-f580-4544-b856-ae48bb7240b9
90a9098e-b481-4894-9255-84da9fbd0aa1
9d9f587e-3904-4066-aeff-ad232f00a267
a7b70710-be13-4b65-9dbd-32c33b09ef2f
197048d2-022f-4a4c-8205-2c184a994ca5
5de40320-2b2a-4b07-8798-655b59f606b8
0739511a-9659-43ef-9862-79aa02180148
4e634ca3-7dc6-4c43-867e-864253d80ce4
47e2165a-e643-4d29-85e1-4c0a356815c6
10fe3f90-63cc-4c3b-9079-d83a20c3b1d4
46a7778e-dca8-4a95-b38a-e3c99a58da73
6167c97a-34cd-4f28-bb5b-88593af6b0fa

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: