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)

01992b39-3d49-7077-b211-e97379668621
01992b39-3d49-727f-921e-6a9638b62acc
01992b39-3d49-73c3-b813-1fc8856ac424
01992b39-3d49-74ea-996e-fd62e628f078
01992b39-3d49-7605-9a2c-f83bf05fe2ba
01992b39-3d49-7723-a88a-483abeb0f8eb
01992b39-3d49-783e-b015-27e6e42f31a6
01992b39-3d49-79b3-ac6a-c66f961358cc
01992b39-3d49-7b07-99f0-9004057ef3ba
01992b39-3d49-7c29-a9d5-fa97c30343aa
01992b39-3d49-7d4c-82d5-c4ed1cb5b1e8
01992b39-3d49-7e67-9d6d-fe1dca43549d
01992b39-3d49-7f86-b437-c630bd7f5991
01992b39-3d4a-70a4-9809-e75df3aec97f
01992b39-3d4a-71c3-9e9f-6f036dd47137

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)

1f08cfa7-f6b6-6360-b8b4-4cf95d479851
1f08cfa7-f6b6-6522-b8b4-4cf95d479851
1f08cfa7-f6b6-6612-b8b4-4cf95d479851
1f08cfa7-f6b6-66e4-b8b4-4cf95d479851
1f08cfa7-f6b6-67b6-b8b4-4cf95d479851
1f08cfa7-f6b6-687e-b8b4-4cf95d479851
1f08cfa7-f6b6-693c-b8b4-4cf95d479851
1f08cfa7-f6b6-69fa-b8b4-4cf95d479851
1f08cfa7-f6b6-6acc-b8b4-4cf95d479851
1f08cfa7-f6b6-6b8a-b8b4-4cf95d479851
1f08cfa7-f6b6-6cc0-b8b4-4cf95d479851
1f08cfa7-f6b6-6d92-b8b4-4cf95d479851
1f08cfa7-f6b6-6e5a-b8b4-4cf95d479851
1f08cfa7-f6b6-6f22-b8b4-4cf95d479851
1f08cfa7-f6b6-6fe0-b8b4-4cf95d479851

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)

9b014137-e05f-4629-8549-8748d694f9b4
d90f0e7f-affb-430b-9ada-f082abd591af
87860de8-8247-43b3-b3a5-50c6adf55480
3277e7d6-2ff1-4474-b2cc-c96258fa4a60
922cf0a2-a025-4a2d-8387-2043ccf44d76
a9665b2d-a2fe-42de-ae00-1d41cc2ed0c0
8520163f-a649-4e4a-9834-52c9a8f8a875
1ed23318-9734-4f83-a4f4-c457a1902bbd
362848a6-526a-45d8-95e8-54ce5dd75c2d
27f7cd22-3f26-468c-984f-d29fd941aa87
f6a91d83-151f-45e5-a083-2ae032c81e20
f6d3fbf4-f257-415a-b5a9-077d6ab64987
034d9dcc-e4bd-4f70-8933-53d8f627b011
e6dd0d0d-2504-44e3-a742-2c7df4796b2b
6c82fde7-8b1a-4676-a683-cef1f6a16122

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)

7f6b76d4-8cfa-11f0-b8b4-4cf95d479851
7f6b776a-8cfa-11f0-b8b4-4cf95d479851
7f6b77f6-8cfa-11f0-b8b4-4cf95d479851
7f6b7882-8cfa-11f0-b8b4-4cf95d479851
7f6b78f0-8cfa-11f0-b8b4-4cf95d479851
7f6b795e-8cfa-11f0-b8b4-4cf95d479851
7f6b79cc-8cfa-11f0-b8b4-4cf95d479851
7f6b7a3a-8cfa-11f0-b8b4-4cf95d479851
7f6b7a94-8cfa-11f0-b8b4-4cf95d479851
7f6b7b02-8cfa-11f0-b8b4-4cf95d479851
7f6b7b70-8cfa-11f0-b8b4-4cf95d479851
7f6b7bd4-8cfa-11f0-b8b4-4cf95d479851
7f6b7c38-8cfa-11f0-b8b4-4cf95d479851
7f6b7c9c-8cfa-11f0-b8b4-4cf95d479851
7f6b7d0a-8cfa-11f0-b8b4-4cf95d479851

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)

306f9823-0705-8b0f-87e9-5ce32bd83b97
f4539923-0705-8b0f-87e9-5ce32bd83b97
7c2a9a23-0705-8b0f-87e9-5ce32bd83b97
129f9b23-0705-8b0f-87e9-5ce32bd83b97
3e2e9c23-0705-8b0f-87e9-5ce32bd83b97
e2659d23-0705-8b0f-87e9-5ce32bd83b97
ba2b9e23-0705-8b0f-87e9-5ce32bd83b97
40f99f23-0705-8b0f-87e9-5ce32bd83b97
9ac9a023-0705-8b0f-87e9-5ce32bd83b97
ec86a123-0705-8b0f-87e9-5ce32bd83b97
0f3ea223-0705-8b0f-87e9-5ce32bd83b97
1e5ca323-0705-8b0f-87e9-5ce32bd83b97
be8aa423-0705-8b0f-87e9-5ce32bd83b97
05ada523-0705-8b0f-87e9-5ce32bd83b97
ae4aa623-0705-8b0f-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: