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)

019cc688-e6f4-72b5-8c01-cf83ce9a55f8
019cc688-e6f4-744e-999a-323628430dda
019cc688-e6f4-75c7-b551-1842580b7082
019cc688-e6f4-76ee-a5e6-f138d37f298d
019cc688-e6f4-7809-953e-85178d73b076
019cc688-e6f4-7927-ae75-716894bd6c03
019cc688-e6f4-7a3e-8624-eaa792210017
019cc688-e6f4-7b59-95a1-f3be36b1e4ec
019cc688-e6f4-7c6f-ba79-798191822dc3
019cc688-e6f4-7d8a-a09c-d4b12316800a
019cc688-e6f4-7ea4-84b7-494627d995a0
019cc688-e6f4-7fbb-874b-ee5546ccc2ad
019cc688-e6f5-70d5-8830-17fa0e0b5192
019cc688-e6f5-71ec-83c6-9c9f8bab1319
019cc688-e6f5-7307-ac0c-24575b461f2e

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)

1f119dd5-73f0-6d7c-a2f0-4cf95d479851
1f119dd5-73f0-6f02-a2f0-4cf95d479851
1f119dd5-73f0-6fde-a2f0-4cf95d479851
1f119dd5-73f1-60b0-a2f0-4cf95d479851
1f119dd5-73f1-616e-a2f0-4cf95d479851
1f119dd5-73f1-6236-a2f0-4cf95d479851
1f119dd5-73f1-62fe-a2f0-4cf95d479851
1f119dd5-73f1-63bc-a2f0-4cf95d479851
1f119dd5-73f1-647a-a2f0-4cf95d479851
1f119dd5-73f1-6542-a2f0-4cf95d479851
1f119dd5-73f1-6678-a2f0-4cf95d479851
1f119dd5-73f1-6740-a2f0-4cf95d479851
1f119dd5-73f1-6808-a2f0-4cf95d479851
1f119dd5-73f1-68bc-a2f0-4cf95d479851
1f119dd5-73f1-697a-a2f0-4cf95d479851

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)

8c0e0232-c4cf-40ad-a748-868b511cf002
9651e68c-4844-441f-8866-6f1967214cdd
dc11ddf2-9145-40ad-9d3f-cb9710096ccc
1b94a659-2e55-4686-b1b7-5f9cef5c8f4a
77b9cb0e-3e1f-40b1-80a8-0ad6c0b20420
c6107639-f726-4f74-a604-eb240471b2ff
b54e63e8-bbeb-4eaf-addc-3bfc56b02939
beecbfa5-8a6b-4306-8712-b2e9e53d7af5
3e27133e-3b70-4faf-b92d-3d95a020e70e
6c264684-2fe8-441a-8e7d-e3e438745690
a1909f07-30ae-4dab-ae15-e32ac191fc8c
2d112a38-d995-4578-9393-6911c86767e8
8f326e82-4ddb-4ff1-9912-967803800cb1
8bd94ceb-b1f8-4b51-8c91-e5fd4c53a71a
898102d8-70d6-4dea-8c0a-0d12603fea14

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)

573f1e98-19dd-11f1-a2f0-4cf95d479851
573f1f06-19dd-11f1-a2f0-4cf95d479851
573f1f6a-19dd-11f1-a2f0-4cf95d479851
573f1fce-19dd-11f1-a2f0-4cf95d479851
573f2032-19dd-11f1-a2f0-4cf95d479851
573f208c-19dd-11f1-a2f0-4cf95d479851
573f20f0-19dd-11f1-a2f0-4cf95d479851
573f214a-19dd-11f1-a2f0-4cf95d479851
573f21ae-19dd-11f1-a2f0-4cf95d479851
573f2212-19dd-11f1-a2f0-4cf95d479851
573f226c-19dd-11f1-a2f0-4cf95d479851
573f22c6-19dd-11f1-a2f0-4cf95d479851
573f232a-19dd-11f1-a2f0-4cf95d479851
573f238e-19dd-11f1-a2f0-4cf95d479851
573f23fc-19dd-11f1-a2f0-4cf95d479851

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)

b968bd06-0801-8204-87ea-5ce32bd83b97
e678be06-0801-8204-87ea-5ce32bd83b97
c3e8bf06-0801-8204-87ea-5ce32bd83b97
5a99c006-0801-8204-87ea-5ce32bd83b97
a1a1c106-0801-8204-87ea-5ce32bd83b97
629cc306-0801-8204-87ea-5ce32bd83b97
7d41c406-0801-8204-87ea-5ce32bd83b97
35fbc506-0801-8204-87ea-5ce32bd83b97
1d6ec606-0801-8204-87ea-5ce32bd83b97
eaeec706-0801-8204-87ea-5ce32bd83b97
88f5c806-0801-8204-87ea-5ce32bd83b97
0363c906-0801-8204-87ea-5ce32bd83b97
70b3ca06-0801-8204-87ea-5ce32bd83b97
4df6cb06-0801-8204-87ea-5ce32bd83b97
6d89cc06-0801-8204-87ea-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: