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)

019e418c-c798-7f59-9836-124c77664a5d
019e418c-c799-70e6-b724-cea36b1e695b
019e418c-c799-721d-bc13-1a8b71f0f4dc
019e418c-c799-733c-9edb-f70209d07ef9
019e418c-c799-7452-8d66-692356bab614
019e418c-c799-7569-a02f-ef3cf16dbf24
019e418c-c799-767b-a08a-56052e8ec467
019e418c-c799-778e-b88c-a28c95347f54
019e418c-c799-78a0-92f1-1c54fc39ae31
019e418c-c799-79b3-b213-b97772b34c1b
019e418c-c799-7ac5-ba21-dfa20e566898
019e418c-c799-7bdc-829a-efbf6e259647
019e418c-c799-7cee-bd19-d9d6279337e3
019e418c-c799-7e05-8729-adffacb4ec15
019e418c-c799-7f17-a8e8-1278b1a300b3

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)

1f153b29-eb63-6144-a17a-4cf95d479851
1f153b29-eb63-62de-a17a-4cf95d479851
1f153b29-eb63-63c4-a17a-4cf95d479851
1f153b29-eb63-6496-a17a-4cf95d479851
1f153b29-eb63-6568-a17a-4cf95d479851
1f153b29-eb63-6630-a17a-4cf95d479851
1f153b29-eb63-66f8-a17a-4cf95d479851
1f153b29-eb63-67c0-a17a-4cf95d479851
1f153b29-eb63-6892-a17a-4cf95d479851
1f153b29-eb63-695a-a17a-4cf95d479851
1f153b29-eb63-6aa4-a17a-4cf95d479851
1f153b29-eb63-6b80-a17a-4cf95d479851
1f153b29-eb63-6c52-a17a-4cf95d479851
1f153b29-eb63-6d10-a17a-4cf95d479851
1f153b29-eb63-6dd8-a17a-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)

9eb63eb4-53b2-11f1-a17a-4cf95d479851
9eb63f22-53b2-11f1-a17a-4cf95d479851
9eb63f86-53b2-11f1-a17a-4cf95d479851
9eb63ff4-53b2-11f1-a17a-4cf95d479851
9eb6404e-53b2-11f1-a17a-4cf95d479851
9eb640bc-53b2-11f1-a17a-4cf95d479851
9eb64120-53b2-11f1-a17a-4cf95d479851
9eb6418e-53b2-11f1-a17a-4cf95d479851
9eb641f2-53b2-11f1-a17a-4cf95d479851
9eb64256-53b2-11f1-a17a-4cf95d479851
9eb64378-53b2-11f1-a17a-4cf95d479851
9eb643e6-53b2-11f1-a17a-4cf95d479851
9eb6444a-53b2-11f1-a17a-4cf95d479851
9eb644b8-53b2-11f1-a17a-4cf95d479851
9eb6451c-53b2-11f1-a17a-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)

ef49b819-6404-8b08-87ea-5ce32bd83b97
6689b919-6404-8b08-87ea-5ce32bd83b97
d7cdba19-6404-8b08-87ea-5ce32bd83b97
d99abb19-6404-8b08-87ea-5ce32bd83b97
9dacbd19-6404-8b08-87ea-5ce32bd83b97
5868be19-6404-8b08-87ea-5ce32bd83b97
3d1abf19-6404-8b08-87ea-5ce32bd83b97
cd36c019-6404-8b08-87ea-5ce32bd83b97
949bc119-6404-8b08-87ea-5ce32bd83b97
77bcc219-6404-8b08-87ea-5ce32bd83b97
66ddc319-6404-8b08-87ea-5ce32bd83b97
3bc1c419-6404-8b08-87ea-5ce32bd83b97
bed2c519-6404-8b08-87ea-5ce32bd83b97
474ec619-6404-8b08-87ea-5ce32bd83b97
da48c719-6404-8b08-87ea-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)

9aa30898-7ee5-48d6-bf00-bf93a5ecd987
cde6d5ac-afed-4660-820c-f2c34a529e42
1d395586-8a36-44fc-b408-2ac9f3e0aed6
b0cc289b-68dc-4a78-a552-e25c1eec0120
b0b30208-a6a3-4906-8376-3a380ff36651
cc2d1876-3835-4d21-bfc7-94bf17abe484
ad69165f-0200-446e-88c2-8fd1024c4fcf
fe402032-397b-4ab5-b77d-e1805c091d1a
5d810377-25ab-438d-bfa8-86019f70f754
481ec31d-819e-44d2-9feb-4d149f73ca70
0b85fba2-0498-4945-9e72-c28c9bf84dbb
d0d8d2bf-709c-4bdc-9d58-a67642cf6ca7
f5a3fe42-8545-4850-b49b-8d7588cd2ecb
a49a9034-41a2-4cb4-92b6-7e2fed623d72
da121a05-d751-42c5-9aff-d6d5af775b21

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: