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)

01953169-3714-7144-adba-bfea314372c6
01953169-3715-735d-ba66-f611e08261b5
01953169-3715-74b5-89af-ca5dac28baa0
01953169-3715-75dc-9f8c-4a29797cc7a3
01953169-3715-76fe-b58f-2c8e5241b94b
01953169-3715-7819-839e-29e5421e6aa0
01953169-3715-7938-83a5-92806905b1e9
01953169-3715-7a57-bf2a-8da16c5935cb
01953169-3715-7b71-845c-c08d683f40e1
01953169-3715-7c90-8f73-1847188eca8e
01953169-3715-7daa-b010-a64d20f58b60
01953169-3715-7ec5-82e9-99b346893e6f
01953169-3715-7fe0-8434-5cf99dc49963
01953169-3716-70fa-98be-afbfdd02de2b
01953169-3716-7219-aad1-706073afd77a

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)

1eff1ac3-1791-674a-99c1-4cf95d479851
1eff1ac3-1791-695c-99c1-4cf95d479851
1eff1ac3-1791-6a42-99c1-4cf95d479851
1eff1ac3-1791-6b0a-99c1-4cf95d479851
1eff1ac3-1791-6bc8-99c1-4cf95d479851
1eff1ac3-1791-6c86-99c1-4cf95d479851
1eff1ac3-1791-6d44-99c1-4cf95d479851
1eff1ac3-1791-6df8-99c1-4cf95d479851
1eff1ac3-1791-6eb6-99c1-4cf95d479851
1eff1ac3-1791-6f74-99c1-4cf95d479851
1eff1ac3-1792-60fa-99c1-4cf95d479851
1eff1ac3-1792-61d6-99c1-4cf95d479851
1eff1ac3-1792-629e-99c1-4cf95d479851
1eff1ac3-1792-635c-99c1-4cf95d479851
1eff1ac3-1792-641a-99c1-4cf95d479851

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)

5edcb16c-00fe-4edb-bef3-ad657ccc2418
fc51d163-305e-4371-8d15-b8ba6b100920
d3ff5216-33fb-4414-96aa-745d301a3410
acdd9f79-ffc9-49b8-923b-ffc80558993d
93141a5d-5504-41df-a0c0-89e09b12aaf0
7363398b-e7d9-4a1e-a596-77e8943545ed
2bb3fd83-0304-45bc-94be-d415c5686ae9
44a3eae8-ba4b-4f47-9e92-ebc5b7d18cd6
242ef6ee-d82b-4ba9-972b-f46868a53ca2
31d9c57f-57fc-40e3-a5f2-b5dcab468a3e
4229bd9d-f6c7-4bc5-8a03-680cff72621b
9197e071-302b-46e5-bf9b-9996acbae492
18ada0b9-49aa-46bb-93a5-226fa13070bb
586f253d-8bef-4c5a-8812-2efe104ff526
9314b597-e540-4ed4-8f52-2ac78394f67c

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)

31792938-f1ac-11ef-99c1-4cf95d479851
3179299c-f1ac-11ef-99c1-4cf95d479851
31792a00-f1ac-11ef-99c1-4cf95d479851
31792a5a-f1ac-11ef-99c1-4cf95d479851
31792abe-f1ac-11ef-99c1-4cf95d479851
31792b18-f1ac-11ef-99c1-4cf95d479851
31792b72-f1ac-11ef-99c1-4cf95d479851
31792be0-f1ac-11ef-99c1-4cf95d479851
31792c3a-f1ac-11ef-99c1-4cf95d479851
31792c9e-f1ac-11ef-99c1-4cf95d479851
31792cf8-f1ac-11ef-99c1-4cf95d479851
31792d52-f1ac-11ef-99c1-4cf95d479851
31792dac-f1ac-11ef-99c1-4cf95d479851
31792e10-f1ac-11ef-99c1-4cf95d479851
31792e6a-f1ac-11ef-99c1-4cf95d479851

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)

d1a8d821-016e-8036-87e9-5ce32bd83b96
92a2d921-016e-8036-87e9-5ce32bd83b96
98b9da21-016e-8036-87e9-5ce32bd83b96
411edb21-016e-8036-87e9-5ce32bd83b96
7508dc21-016e-8036-87e9-5ce32bd83b96
9984dd21-016e-8036-87e9-5ce32bd83b96
0da8de21-016e-8036-87e9-5ce32bd83b96
5a5adf21-016e-8036-87e9-5ce32bd83b96
8c9de021-016e-8036-87e9-5ce32bd83b96
71c0e221-016e-8036-87e9-5ce32bd83b96
1362e321-016e-8036-87e9-5ce32bd83b96
a80de421-016e-8036-87e9-5ce32bd83b96
1d00e521-016e-8036-87e9-5ce32bd83b96
47e0e621-016e-8036-87e9-5ce32bd83b96
4d7ee721-016e-8036-87e9-5ce32bd83b96

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: