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)

0196485d-c8fa-7ca8-9e63-d3ecb4543bda
0196485d-c8fa-7e32-a699-c73485711c5b
0196485d-c8fa-7f71-be21-9a5a70c6e3fc
0196485d-c8fb-7090-8687-176c02ece164
0196485d-c8fb-71af-83b9-2eccecce0c2f
0196485d-c8fb-72c9-a5ba-2b216c4271f3
0196485d-c8fb-7411-bee8-dec53251dd44
0196485d-c8fb-7530-8298-57079871cf9d
0196485d-c8fb-764a-9294-7a0a59de6c5d
0196485d-c8fb-7765-b28d-ab179f1860f2
0196485d-c8fb-787b-8442-fb1229e09a7c
0196485d-c8fb-799e-b5a5-974b292f29b7
0196485d-c8fb-7ab9-94ac-46c161504ee1
0196485d-c8fb-7bd3-bb92-f5f0eef78325
0196485d-c8fb-7cea-835f-9af1aebba475

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)

1f01c3ce-2fc3-6000-a2e7-4cf95d479851
1f01c3ce-2fc3-6172-a2e7-4cf95d479851
1f01c3ce-2fc3-624e-a2e7-4cf95d479851
1f01c3ce-2fc3-6320-a2e7-4cf95d479851
1f01c3ce-2fc3-63de-a2e7-4cf95d479851
1f01c3ce-2fc3-649c-a2e7-4cf95d479851
1f01c3ce-2fc3-655a-a2e7-4cf95d479851
1f01c3ce-2fc3-6618-a2e7-4cf95d479851
1f01c3ce-2fc3-66d6-a2e7-4cf95d479851
1f01c3ce-2fc3-6794-a2e7-4cf95d479851
1f01c3ce-2fc3-68ca-a2e7-4cf95d479851
1f01c3ce-2fc3-6992-a2e7-4cf95d479851
1f01c3ce-2fc3-6a46-a2e7-4cf95d479851
1f01c3ce-2fc3-6b04-a2e7-4cf95d479851
1f01c3ce-2fc3-6bc2-a2e7-4cf95d479851

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)

e8dbd8b6-daba-4cfe-b2fd-281c129befa8
592ed661-c272-4164-83a4-87c08bee9f2a
784fdab4-3b58-4ac4-b80a-f788ffefb3ae
54ffdd70-6163-45bc-b44b-0b016487bc84
1798519d-b392-4fe9-9dd3-8ad4e53f8918
57d1953d-b830-45ba-947a-a0241c498e88
d93e5ef8-6c6b-4c75-882b-817a8d80bd7f
13987a5c-1b0c-4a97-b808-e38d62581f04
a451cbca-dbdf-4432-a524-900d755c0f59
94f82d8f-c832-47e7-9554-e465b66f94f0
4904d926-d894-4db6-a4c2-2d8670c4ea59
d78d247e-c023-4588-8d32-1005a1b7d862
b5813ec6-fcb1-49b2-99b2-6b0600352b51
d25da1f7-40ee-43ba-a73e-a249e92dd241
55909755-f62b-44a5-b6ae-f1185ad77936

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)

e2fc40e0-1c3c-11f0-a2e7-4cf95d479851
e2fc4144-1c3c-11f0-a2e7-4cf95d479851
e2fc41a8-1c3c-11f0-a2e7-4cf95d479851
e2fc420c-1c3c-11f0-a2e7-4cf95d479851
e2fc4266-1c3c-11f0-a2e7-4cf95d479851
e2fc42c0-1c3c-11f0-a2e7-4cf95d479851
e2fc4324-1c3c-11f0-a2e7-4cf95d479851
e2fc4388-1c3c-11f0-a2e7-4cf95d479851
e2fc43ec-1c3c-11f0-a2e7-4cf95d479851
e2fc4446-1c3c-11f0-a2e7-4cf95d479851
e2fc44aa-1c3c-11f0-a2e7-4cf95d479851
e2fc4504-1c3c-11f0-a2e7-4cf95d479851
e2fc455e-1c3c-11f0-a2e7-4cf95d479851
e2fc45c2-1c3c-11f0-a2e7-4cf95d479851
e2fc461c-1c3c-11f0-a2e7-4cf95d479851

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)

77cc0708-0260-806c-87e9-5ce32bd83b96
89370808-0260-806c-87e9-5ce32bd83b96
236a0908-0260-806c-87e9-5ce32bd83b96
75130a08-0260-806c-87e9-5ce32bd83b96
b5820b08-0260-806c-87e9-5ce32bd83b96
0c3d0c08-0260-806c-87e9-5ce32bd83b96
8e600e08-0260-806c-87e9-5ce32bd83b96
feee0f08-0260-806c-87e9-5ce32bd83b96
42f61008-0260-806c-87e9-5ce32bd83b96
03881108-0260-806c-87e9-5ce32bd83b96
c2641208-0260-806c-87e9-5ce32bd83b96
9afc1308-0260-806c-87e9-5ce32bd83b96
3b1e1408-0260-806c-87e9-5ce32bd83b96
f1651508-0260-806c-87e9-5ce32bd83b96
e61d1608-0260-806c-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: