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)

019b963b-4cb8-7130-ad76-78c2f47f1ee5
019b963b-4cb8-72cd-afef-4711b2e5c85f
019b963b-4cb8-7405-93a2-c5a68e139480
019b963b-4cb8-7523-9376-5e8a0a12d66b
019b963b-4cb8-763a-a9b5-e80be2068b97
019b963b-4cb8-7750-89eb-c90eb39fb199
019b963b-4cb8-786b-905f-b95f7f89fb74
019b963b-4cb8-7982-a71e-4a72d6fa85b7
019b963b-4cb8-7a94-8da7-11d83fde4bea
019b963b-4cb8-7ba6-87bb-225fb252a35a
019b963b-4cb8-7cb9-a2fb-8ec2a76d2893
019b963b-4cb8-7dcf-9779-d21c39187887
019b963b-4cb8-7ee6-b320-4ec134d38f29
019b963b-4cb8-7ff8-a6af-7bc973a7661b
019b963b-4cb9-710f-8fe0-5a5537a03bbf

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)

1f0eb6e7-fe64-624c-a96e-4cf95d479851
1f0eb6e7-fe64-63d2-a96e-4cf95d479851
1f0eb6e7-fe64-64b8-a96e-4cf95d479851
1f0eb6e7-fe64-6594-a96e-4cf95d479851
1f0eb6e7-fe64-665c-a96e-4cf95d479851
1f0eb6e7-fe64-672e-a96e-4cf95d479851
1f0eb6e7-fe64-6800-a96e-4cf95d479851
1f0eb6e7-fe64-68c8-a96e-4cf95d479851
1f0eb6e7-fe64-6990-a96e-4cf95d479851
1f0eb6e7-fe64-6a58-a96e-4cf95d479851
1f0eb6e7-fe64-6ba2-a96e-4cf95d479851
1f0eb6e7-fe64-6c9c-a96e-4cf95d479851
1f0eb6e7-fe64-6de6-a96e-4cf95d479851
1f0eb6e7-fe64-6f26-a96e-4cf95d479851
1f0eb6e7-fe65-6084-a96e-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)

f1cae256-b9a4-48a9-bf4f-82ab7adf297c
efac7a8b-34b1-404c-936c-b730d8a52b5b
68d8917b-08fb-49e7-87aa-f502b5b5f4f9
6a8cc484-6d75-4a24-bb6f-55e6f7316a79
ebce0e00-d0bf-4b9a-a3e1-3174269f5401
8fc7430e-1e14-4567-9b30-9327dff5f6f7
d6ce4db3-a591-403c-b7ea-0e6fbfa0e78d
f7db8dc6-1560-4acf-a653-51b3d778d017
a1b2c2bb-b0e8-4ef7-81da-523a36be338f
cf2d5c1a-4d76-494d-af43-bacf5074c552
95c1f28c-6cd1-4464-96e2-8d3e39eca5d1
ccd70e0b-40f5-4262-8a37-56c77c462029
acaa8382-a08c-4441-92ec-2d484ece2c42
c4b0e955-1c50-41da-a922-549edbc17d3d
8fd9cc09-fef4-4c18-9aa4-c467f4762fb3

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)

7fe65624-eb6e-11f0-a96e-4cf95d479851
7fe65688-eb6e-11f0-a96e-4cf95d479851
7fe656ec-eb6e-11f0-a96e-4cf95d479851
7fe65746-eb6e-11f0-a96e-4cf95d479851
7fe657b4-eb6e-11f0-a96e-4cf95d479851
7fe65818-eb6e-11f0-a96e-4cf95d479851
7fe6587c-eb6e-11f0-a96e-4cf95d479851
7fe658e0-eb6e-11f0-a96e-4cf95d479851
7fe65944-eb6e-11f0-a96e-4cf95d479851
7fe659b2-eb6e-11f0-a96e-4cf95d479851
7fe65a20-eb6e-11f0-a96e-4cf95d479851
7fe65a7a-eb6e-11f0-a96e-4cf95d479851
7fe65ade-eb6e-11f0-a96e-4cf95d479851
7fe65b42-eb6e-11f0-a96e-4cf95d479851
7fe65ba6-eb6e-11f0-a96e-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)

efc9522f-8600-8700-87ea-5ce32bd83b97
bca9532f-8600-8700-87ea-5ce32bd83b97
ba9a542f-8600-8700-87ea-5ce32bd83b97
6c3b552f-8600-8700-87ea-5ce32bd83b97
49d1562f-8600-8700-87ea-5ce32bd83b97
09de572f-8600-8700-87ea-5ce32bd83b97
a63a582f-8600-8700-87ea-5ce32bd83b97
3818592f-8600-8700-87ea-5ce32bd83b97
08125a2f-8600-8700-87ea-5ce32bd83b97
803c5b2f-8600-8700-87ea-5ce32bd83b97
2e905c2f-8600-8700-87ea-5ce32bd83b97
8be85d2f-8600-8700-87ea-5ce32bd83b97
79f35e2f-8600-8700-87ea-5ce32bd83b97
4fec5f2f-8600-8700-87ea-5ce32bd83b97
f253602f-8600-8700-87ea-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: