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)

01948d11-162a-7832-bd51-a9f0214a0e19
01948d11-162a-7a11-8575-9039d2d9b312
01948d11-162a-7b9a-b4f9-04921fc91b53
01948d11-162a-7cfe-aa00-f8a775a62bb3
01948d11-162a-7e5b-b0c3-79176e1d71e2
01948d11-162a-7fbb-8f2c-fde53db55933
01948d11-162b-710f-bfe0-b71ed9a08ee1
01948d11-162b-7267-a0f9-571ca0fa3011
01948d11-162b-73bb-9ad7-f3a0e2ab0148
01948d11-162b-7513-84b7-b0a862690c19
01948d11-162b-769c-89d3-d7638e1e4584
01948d11-162b-77ec-b2d0-e02aa0e816ea
01948d11-162b-790f-90d3-8cf74db68d66
01948d11-162b-7a29-9add-5abedd9837d7
01948d11-162b-7b44-a92d-e22149e339c9

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)

1efd8987-ef34-6f0e-8806-4cf95d479851
1efd8987-ef35-60bc-8806-4cf95d479851
1efd8987-ef35-61a2-8806-4cf95d479851
1efd8987-ef35-627e-8806-4cf95d479851
1efd8987-ef35-6350-8806-4cf95d479851
1efd8987-ef35-6418-8806-4cf95d479851
1efd8987-ef35-64e0-8806-4cf95d479851
1efd8987-ef35-65b2-8806-4cf95d479851
1efd8987-ef35-667a-8806-4cf95d479851
1efd8987-ef35-6738-8806-4cf95d479851
1efd8987-ef35-6918-8806-4cf95d479851
1efd8987-ef35-69f4-8806-4cf95d479851
1efd8987-ef35-6abc-8806-4cf95d479851
1efd8987-ef35-6b84-8806-4cf95d479851
1efd8987-ef35-6c4c-8806-4cf95d479851

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)

b8f71808-16c0-4144-ba3d-9fed7b84b405
c4029b6c-ec3c-466a-8059-478ce3095b1a
0f332a4b-0341-43a7-82c9-e795d4911bff
d01306d7-5c99-4721-8a88-002362a275dc
37f4e74c-e9aa-4d1b-8c51-3273bd00244c
9cfc876a-0502-4cf9-87b6-d7679e53c994
6867e97f-73b6-4fe8-8c92-122ee1c0eab3
3c7b402f-2918-42f5-9b77-c7d9ff91117f
edd50ba0-eada-4c33-8b62-23aa6e629be2
be5f3d00-21ea-40d5-82c6-340871b06244
e7c4cff5-e27f-4dfc-af16-f7a6eaa7aa34
704ccbf2-fa76-4c90-a324-c3fa9be7067e
34b15f83-28ef-42b9-a106-3624636bd9ea
686f8366-5ee8-4a89-b825-6206c145e011
20eee861-b792-4ea5-8d09-c0f66450d32c

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)

7ef36192-d898-11ef-8806-4cf95d479851
7ef36200-d898-11ef-8806-4cf95d479851
7ef3626e-d898-11ef-8806-4cf95d479851
7ef362e6-d898-11ef-8806-4cf95d479851
7ef3634a-d898-11ef-8806-4cf95d479851
7ef363b8-d898-11ef-8806-4cf95d479851
7ef3641c-d898-11ef-8806-4cf95d479851
7ef36480-d898-11ef-8806-4cf95d479851
7ef364da-d898-11ef-8806-4cf95d479851
7ef3653e-d898-11ef-8806-4cf95d479851
7ef365ac-d898-11ef-8806-4cf95d479851
7ef36610-d898-11ef-8806-4cf95d479851
7ef36674-d898-11ef-8806-4cf95d479851
7ef366d8-d898-11ef-8806-4cf95d479851
7ef36732-d898-11ef-8806-4cf95d479851

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)

cf2ad322-01ec-8016-87e9-5ce32bd83b96
bc39d422-01ec-8016-87e9-5ce32bd83b96
d661d522-01ec-8016-87e9-5ce32bd83b96
4a3bd622-01ec-8016-87e9-5ce32bd83b96
7016d722-01ec-8016-87e9-5ce32bd83b96
3647d922-01ec-8016-87e9-5ce32bd83b96
407bda22-01ec-8016-87e9-5ce32bd83b96
1b5adb22-01ec-8016-87e9-5ce32bd83b96
3a2edc22-01ec-8016-87e9-5ce32bd83b96
388fdd22-01ec-8016-87e9-5ce32bd83b96
3269de22-01ec-8016-87e9-5ce32bd83b96
3e69df22-01ec-8016-87e9-5ce32bd83b96
e58be022-01ec-8016-87e9-5ce32bd83b96
1aa1e122-01ec-8016-87e9-5ce32bd83b96
6108e222-01ec-8016-87e9-5ce32bd83b96

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: