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)

019babf6-c403-7229-8d39-795f3e5d4c8c
019babf6-c403-73bb-bd4b-17f3e95dc137
019babf6-c403-74fa-835d-46fc3f09c446
019babf6-c403-761d-9ac3-7d3c0b487d3c
019babf6-c403-76a8-bae6-9af104b487cf
019babf6-c403-77bf-8488-fffd1d72c012
019babf6-c403-78da-8ec1-aae4083bf57f
019babf6-c403-79f4-9e51-eb90f8e8a538
019babf6-c403-7b0f-8063-5a33836387f6
019babf6-c403-7c25-b820-9a5faab72764
019babf6-c403-7d3c-8e45-92f6bdba0dd2
019babf6-c403-7e52-9673-2734f25aca3e
019babf6-c403-7f69-824c-7913f3aa8c76
019babf6-c404-707f-a935-b9151d2230e9
019babf6-c404-719e-9809-f20c34c71078

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)

1f0eebf6-aca2-63fc-ac9e-4cf95d479851
1f0eebf6-aca2-658c-ac9e-4cf95d479851
1f0eebf6-aca2-667c-ac9e-4cf95d479851
1f0eebf6-aca2-674e-ac9e-4cf95d479851
1f0eebf6-aca2-6816-ac9e-4cf95d479851
1f0eebf6-aca2-68de-ac9e-4cf95d479851
1f0eebf6-aca2-699c-ac9e-4cf95d479851
1f0eebf6-aca2-6a64-ac9e-4cf95d479851
1f0eebf6-aca2-6b2c-ac9e-4cf95d479851
1f0eebf6-aca2-6bea-ac9e-4cf95d479851
1f0eebf6-aca2-6d16-ac9e-4cf95d479851
1f0eebf6-aca2-6dde-ac9e-4cf95d479851
1f0eebf6-aca2-6ea6-ac9e-4cf95d479851
1f0eebf6-aca2-6f64-ac9e-4cf95d479851
1f0eebf6-aca3-602c-ac9e-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)

45378358-4078-4007-a80e-a40444474cea
0e48db85-d6fd-43d6-ae0d-e91870dc24b9
8cc71084-5750-48b8-8c25-ed81fc24e1d3
ca4023f6-94ad-48f0-a104-8c6d5020e087
9a348dad-f2dc-4c3c-a942-241c7e78d4af
e3e19795-72b6-4bfa-9bfe-32ca85493261
e428c2bc-1fe9-4ed4-a655-0555109b96c4
ee1aa175-4d60-463b-b951-04e9ca4fcf13
ee92d166-124a-4069-af9c-76e89525c894
7ca90e7a-99b1-4bc0-bcae-b046e1af13a4
a91b50d2-025c-4e8c-b2d0-b98aa4b6b21c
a7ffd90d-5a90-41a3-8150-aee6b5672075
5eb7eb8c-9161-4955-b592-4f3f98e438ad
d023ce0e-216c-42e7-869a-d47bef2557eb
d0aa34b3-fd48-45d1-8498-3a5576f4b13b

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)

6aca3540-eebf-11f0-ac9e-4cf95d479851
6aca35a4-eebf-11f0-ac9e-4cf95d479851
6aca3612-eebf-11f0-ac9e-4cf95d479851
6aca3680-eebf-11f0-ac9e-4cf95d479851
6aca36ee-eebf-11f0-ac9e-4cf95d479851
6aca3752-eebf-11f0-ac9e-4cf95d479851
6aca37b6-eebf-11f0-ac9e-4cf95d479851
6aca381a-eebf-11f0-ac9e-4cf95d479851
6aca387e-eebf-11f0-ac9e-4cf95d479851
6aca38d8-eebf-11f0-ac9e-4cf95d479851
6aca3932-eebf-11f0-ac9e-4cf95d479851
6aca3996-eebf-11f0-ac9e-4cf95d479851
6aca39fa-eebf-11f0-ac9e-4cf95d479851
6aca3a5e-eebf-11f0-ac9e-4cf95d479851
6aca3ac2-eebf-11f0-ac9e-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)

9514a022-c301-8b00-87ea-5ce32bd83b97
0beda122-c301-8b00-87ea-5ce32bd83b97
4bf8a322-c301-8b00-87ea-5ce32bd83b97
f4bea422-c301-8b00-87ea-5ce32bd83b97
1f3fa522-c301-8b00-87ea-5ce32bd83b97
3beca622-c301-8b00-87ea-5ce32bd83b97
554ba722-c301-8b00-87ea-5ce32bd83b97
653fa822-c301-8b00-87ea-5ce32bd83b97
1947a922-c301-8b00-87ea-5ce32bd83b97
59d4aa22-c301-8b00-87ea-5ce32bd83b97
800cab22-c301-8b00-87ea-5ce32bd83b97
0022ac22-c301-8b00-87ea-5ce32bd83b97
bd52ad22-c301-8b00-87ea-5ce32bd83b97
9de2ae22-c301-8b00-87ea-5ce32bd83b97
f194af22-c301-8b00-87ea-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: