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)

018f89d6-2154-7b13-9a54-4464ce9729f3
018f89d6-2154-7ccd-bc6f-9e92f420c61a
018f89d6-2154-7e11-a6d7-7d60c3d6bbf0
018f89d6-2154-7f34-a86f-860e5e24eed4
018f89d6-2155-706b-9c19-29c4b31dc4ff
018f89d6-2155-718a-9477-8d1270dd6e22
018f89d6-2155-72a4-84dc-f2039cdff6d6
018f89d6-2155-73bf-b687-c78b7b0cbce8
018f89d6-2155-74da-bf88-84fc94e1c7e7
018f89d6-2155-75f4-8592-e917d426823f
018f89d6-2155-7713-9de1-912ce774a4f8
018f89d6-2155-782e-89a7-6eac3d8679e3
018f89d6-2155-7948-a3b9-c5823f16c96c
018f89d6-2155-7a63-ba75-ca5103de415a
018f89d6-2155-7b7d-a9b3-9b08c6c75411

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)

1ef14ca4-ff76-6ace-956c-4cf95d479851
1ef14ca4-ff76-6ca4-956c-4cf95d479851
1ef14ca4-ff76-6d80-956c-4cf95d479851
1ef14ca4-ff76-6e52-956c-4cf95d479851
1ef14ca4-ff76-6f10-956c-4cf95d479851
1ef14ca4-ff76-6fd8-956c-4cf95d479851
1ef14ca4-ff77-6096-956c-4cf95d479851
1ef14ca4-ff77-617c-956c-4cf95d479851
1ef14ca4-ff77-6244-956c-4cf95d479851
1ef14ca4-ff77-6302-956c-4cf95d479851
1ef14ca4-ff77-646a-956c-4cf95d479851
1ef14ca4-ff77-6532-956c-4cf95d479851
1ef14ca4-ff77-65f0-956c-4cf95d479851
1ef14ca4-ff77-66ae-956c-4cf95d479851
1ef14ca4-ff77-6762-956c-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)

a249c731-52fe-4fd2-a21a-82cca230dad6
5872a7fd-8638-4d27-9de4-47fe144e4fec
91faadc6-316d-4280-aa67-75b28589bef0
a18adcc9-d8e0-49b5-b30e-2d3487fcc09b
2e796fd4-b75a-4435-8b1f-8ef01a1353bd
2e684d13-5d43-482f-aa79-06fc416982e2
51c86764-212d-43a5-903d-c5d97d9eb46c
0da21638-3074-480c-a980-8b37bba9cc7c
7d95e67c-0484-4486-84c9-f7bb88377bbb
b6bddaa3-58ac-4501-a981-290df40e11a1
87170e25-46e4-4023-aa8f-95af3223c1ab
f3269c39-798f-4a06-9a1c-dee8b835a30a
41bc0075-1df0-4dac-9086-baab5946302f
bc1b77b0-6d0b-416d-b7b6-69ff04a36bde
c89d83e2-4728-4495-bc23-283c6efe209e

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)

4ff77c94-14ca-11ef-956c-4cf95d479851
4ff77cee-14ca-11ef-956c-4cf95d479851
4ff77d52-14ca-11ef-956c-4cf95d479851
4ff77dac-14ca-11ef-956c-4cf95d479851
4ff77e06-14ca-11ef-956c-4cf95d479851
4ff77e6a-14ca-11ef-956c-4cf95d479851
4ff77ece-14ca-11ef-956c-4cf95d479851
4ff77f32-14ca-11ef-956c-4cf95d479851
4ff77f96-14ca-11ef-956c-4cf95d479851
4ff77ff0-14ca-11ef-956c-4cf95d479851
4ff7804a-14ca-11ef-956c-4cf95d479851
4ff780ae-14ca-11ef-956c-4cf95d479851
4ff78108-14ca-11ef-956c-4cf95d479851
4ff78162-14ca-11ef-956c-4cf95d479851
4ff781bc-14ca-11ef-956c-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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

9800ee16-00eb-808b-87e8-5ce32bd83b96
948fef16-00eb-808b-87e8-5ce32bd83b96
7901f016-00eb-808b-87e8-5ce32bd83b96
ae5df116-00eb-808b-87e8-5ce32bd83b96
169ff216-00eb-808b-87e8-5ce32bd83b96
557bf416-00eb-808b-87e8-5ce32bd83b96
6170f516-00eb-808b-87e8-5ce32bd83b96
cc02f616-00eb-808b-87e8-5ce32bd83b96
45dbf716-00eb-808b-87e8-5ce32bd83b96
c6cff816-00eb-808b-87e8-5ce32bd83b96
3c2af916-00eb-808b-87e8-5ce32bd83b96
972ffa16-00eb-808b-87e8-5ce32bd83b96
8b53fb16-00eb-808b-87e8-5ce32bd83b96
cfe4fc16-00eb-808b-87e8-5ce32bd83b96
ef76fd16-00eb-808b-87e8-5ce32bd83b96

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: