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)

019a68f4-b117-7a00-aa90-98b9902d6715
019a68f4-b117-7bc3-8491-10d53e307662
019a68f4-b117-7d0b-9203-74db36e086bf
019a68f4-b117-7e32-9d2e-9d4329874281
019a68f4-b117-7f7d-91b3-646494c997d5
019a68f4-b118-70c5-8823-843671f01b30
019a68f4-b118-71e8-a981-e9435650753d
019a68f4-b118-7307-aec3-67e9717076dc
019a68f4-b118-7442-8027-5de2fb897c8e
019a68f4-b118-758a-b066-71b358050aca
019a68f4-b118-76bd-9ac7-328a5d11a43b
019a68f4-b118-77e0-a4f1-055c93cbc2b1
019a68f4-b118-7913-b9a0-b3dd9da84dff
019a68f4-b118-7a5f-a477-a86b414445f5
019a68f4-b118-7b86-8a47-b7ed6b3e724b

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)

1f0bd75e-9c71-69e2-b1bf-4cf95d479851
1f0bd75e-9c71-6ba4-b1bf-4cf95d479851
1f0bd75e-9c71-6c80-b1bf-4cf95d479851
1f0bd75e-9c71-6d52-b1bf-4cf95d479851
1f0bd75e-9c71-6e1a-b1bf-4cf95d479851
1f0bd75e-9c71-6ed8-b1bf-4cf95d479851
1f0bd75e-9c71-6f8c-b1bf-4cf95d479851
1f0bd75e-9c72-604a-b1bf-4cf95d479851
1f0bd75e-9c72-6108-b1bf-4cf95d479851
1f0bd75e-9c72-61c6-b1bf-4cf95d479851
1f0bd75e-9c72-62fc-b1bf-4cf95d479851
1f0bd75e-9c72-63ce-b1bf-4cf95d479851
1f0bd75e-9c72-6482-b1bf-4cf95d479851
1f0bd75e-9c72-6540-b1bf-4cf95d479851
1f0bd75e-9c72-65f4-b1bf-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)

7bae1414-3571-415f-8f89-9857a1f8330c
557fb507-68fb-4721-bdff-49791bad22ff
12fa5c05-8467-49d2-819f-dc67789c4a7f
bdfc375d-28fd-476e-abc0-92c3bc2cefe7
d7418f0f-0c7e-4ec9-bd92-0ecef9af7659
928b6955-63b0-4069-ae75-0935b7d602cd
1ada3778-217d-404f-a467-0764f38630ba
826c418c-60a3-44d7-a3c3-369786adad3b
c8e0ebbf-b1c9-4541-b02e-7aec4d8976c2
2f7fb37e-a8bf-44dd-8956-9558b36a2738
47f136cb-7ac9-4985-a638-e63d03a16519
3502c8d0-9ff0-49f5-8b5e-12fc0bbd67e8
274d6a10-5a41-4bb3-a296-955002b08593
da186dcb-4207-4c7f-8a56-f9c04c69558d
fb587904-3f39-4efa-affb-115c623f32a0

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)

e9c72b30-bd75-11f0-b1bf-4cf95d479851
e9c72b94-bd75-11f0-b1bf-4cf95d479851
e9c72bf8-bd75-11f0-b1bf-4cf95d479851
e9c72c52-bd75-11f0-b1bf-4cf95d479851
e9c72cb6-bd75-11f0-b1bf-4cf95d479851
e9c72d10-bd75-11f0-b1bf-4cf95d479851
e9c72d74-bd75-11f0-b1bf-4cf95d479851
e9c72dce-bd75-11f0-b1bf-4cf95d479851
e9c72e32-bd75-11f0-b1bf-4cf95d479851
e9c72e8c-bd75-11f0-b1bf-4cf95d479851
e9c72ee6-bd75-11f0-b1bf-4cf95d479851
e9c72f40-bd75-11f0-b1bf-4cf95d479851
e9c72f9a-bd75-11f0-b1bf-4cf95d479851
e9c72ffe-bd75-11f0-b1bf-4cf95d479851
e9c73062-bd75-11f0-b1bf-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)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 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) = WRONG!!!
-  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 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)

8de9f139-5303-8913-87e9-5ce32bd83b97
3a06f239-5303-8913-87e9-5ce32bd83b97
5beef339-5303-8913-87e9-5ce32bd83b97
aa49f439-5303-8913-87e9-5ce32bd83b97
0493f539-5303-8913-87e9-5ce32bd83b97
4488f639-5303-8913-87e9-5ce32bd83b97
36e0f739-5303-8913-87e9-5ce32bd83b97
d3e3f939-5303-8913-87e9-5ce32bd83b97
bb78fa39-5303-8913-87e9-5ce32bd83b97
4fa9fb39-5303-8913-87e9-5ce32bd83b97
b3c8fc39-5303-8913-87e9-5ce32bd83b97
8981fd39-5303-8913-87e9-5ce32bd83b97
82e5fe39-5303-8913-87e9-5ce32bd83b97
b362ff39-5303-8913-87e9-5ce32bd83b97
2dc6013a-5303-8913-87e9-5ce32bd83b97

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: