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)

019be329-9650-7e19-941a-3741eb801aff
019be329-9650-7fc3-8687-dd3885d64064
019be329-9651-710b-8e56-a098db4178e1
019be329-9651-71a2-9d33-5b3d997e606b
019be329-9651-72c9-a232-9d75800e57d8
019be329-9651-73ec-9212-4c1d6a6b5fdb
019be329-9651-750b-9168-97dae39927f7
019be329-9651-7629-858b-b72364d25238
019be329-9651-7748-af5c-37bc5a8d08bf
019be329-9651-7863-8678-007f8e4ec682
019be329-9651-7982-9b14-8ad1c5c64a95
019be329-9651-7aa0-9076-a469fe5ab3bf
019be329-9651-7bc3-97b8-10ef1f7e1704
019be329-9651-7ce2-8f43-d3a4d24cc3a8
019be329-9651-7e05-aea6-0079f0c71275

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)

1f0f72b9-c012-623a-940c-4cf95d479851
1f0f72b9-c012-63e8-940c-4cf95d479851
1f0f72b9-c012-64ce-940c-4cf95d479851
1f0f72b9-c012-65aa-940c-4cf95d479851
1f0f72b9-c012-6672-940c-4cf95d479851
1f0f72b9-c012-6744-940c-4cf95d479851
1f0f72b9-c012-680c-940c-4cf95d479851
1f0f72b9-c012-68de-940c-4cf95d479851
1f0f72b9-c012-69a6-940c-4cf95d479851
1f0f72b9-c012-6a6e-940c-4cf95d479851
1f0f72b9-c012-6bb8-940c-4cf95d479851
1f0f72b9-c012-6c8a-940c-4cf95d479851
1f0f72b9-c012-6d52-940c-4cf95d479851
1f0f72b9-c012-6e1a-940c-4cf95d479851
1f0f72b9-c012-6ed8-940c-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)

875f3ee8-ee9f-46f9-b224-c1e73a472cac
2f4c102a-f1d4-4d2c-b779-06cea167e744
9f77e804-b9b2-4dfc-a19a-0b8cf343c35b
0ec12f98-df5b-4059-b5b2-85504dca99e8
a83b27a1-6a00-4a24-b8fa-b6b57ac6c667
e618444b-bd1a-47bd-a352-91d1cf6a7592
82e52b59-3cd1-440b-b55f-f9d162f2f29f
ecf3bff7-476e-49fd-bb8f-a0bc3e4bccc2
66fe1e74-1937-40db-a985-53e099f13f4d
e546c57e-03ae-445a-88cd-58c3a6b5f3a5
110628e1-f324-4285-9f99-999008c98de4
90d527ff-6eba-4a1f-b059-c74bcbdaf9dd
55534022-bca6-435e-a169-b6e88b9e539a
2ab67dcb-0d16-4408-913d-8a6d58220c78
7c568aeb-182f-4623-948b-d26cb0f0be7d

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)

9c013428-f72b-11f0-940c-4cf95d479851
9c01348c-f72b-11f0-940c-4cf95d479851
9c0134e6-f72b-11f0-940c-4cf95d479851
9c01354a-f72b-11f0-940c-4cf95d479851
9c0135ae-f72b-11f0-940c-4cf95d479851
9c013608-f72b-11f0-940c-4cf95d479851
9c01366c-f72b-11f0-940c-4cf95d479851
9c0136da-f72b-11f0-940c-4cf95d479851
9c013748-f72b-11f0-940c-4cf95d479851
9c0137ac-f72b-11f0-940c-4cf95d479851
9c013810-f72b-11f0-940c-4cf95d479851
9c01387e-f72b-11f0-940c-4cf95d479851
9c0138e2-f72b-11f0-940c-4cf95d479851
9c013946-f72b-11f0-940c-4cf95d479851
9c0139aa-f72b-11f0-940c-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)

d742250c-2e00-8601-87ea-5ce32bd83b97
631e260c-2e00-8601-87ea-5ce32bd83b97
e975270c-2e00-8601-87ea-5ce32bd83b97
b8c9280c-2e00-8601-87ea-5ce32bd83b97
febe2a0c-2e00-8601-87ea-5ce32bd83b97
a0a12b0c-2e00-8601-87ea-5ce32bd83b97
ad212c0c-2e00-8601-87ea-5ce32bd83b97
417a2d0c-2e00-8601-87ea-5ce32bd83b97
b7b82e0c-2e00-8601-87ea-5ce32bd83b97
5ebb2f0c-2e00-8601-87ea-5ce32bd83b97
2638300c-2e00-8601-87ea-5ce32bd83b97
6f64310c-2e00-8601-87ea-5ce32bd83b97
1ee3320c-2e00-8601-87ea-5ce32bd83b97
17a6330c-2e00-8601-87ea-5ce32bd83b97
4c28340c-2e00-8601-87ea-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

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: