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)

019c0804-1f3a-7da2-8fe7-b4f75868888e
019c0804-1f3a-7f38-8d07-876d4ff5a024
019c0804-1f3b-7077-b4e1-5856612fda43
019c0804-1f3b-719a-af7e-2e80adf53e98
019c0804-1f3b-72bd-91d8-04994a7c11f2
019c0804-1f3b-73d8-983d-14ea1e04bfa4
019c0804-1f3b-74f6-bb28-e02ac3b297d4
019c0804-1f3b-760d-a80f-f8898a054dbd
019c0804-1f3b-772c-b09d-00f3470c219d
019c0804-1f3b-784a-8f47-0f5bb9a4a6c9
019c0804-1f3b-7965-87bd-a696784630ec
019c0804-1f3b-7a7f-b6e3-838e63bb6803
019c0804-1f3b-7b9e-bccd-e117b05de79e
019c0804-1f3b-7cb5-a87b-a5c2bbe09e0a
019c0804-1f3b-7dc7-80df-a7351a97a886

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)

1f0fccb3-4855-663a-870a-4cf95d479851
1f0fccb3-4855-67c0-870a-4cf95d479851
1f0fccb3-4855-68b0-870a-4cf95d479851
1f0fccb3-4855-6978-870a-4cf95d479851
1f0fccb3-4855-6a36-870a-4cf95d479851
1f0fccb3-4855-6af4-870a-4cf95d479851
1f0fccb3-4855-6bbc-870a-4cf95d479851
1f0fccb3-4855-6c70-870a-4cf95d479851
1f0fccb3-4855-6d2e-870a-4cf95d479851
1f0fccb3-4855-6dec-870a-4cf95d479851
1f0fccb3-4855-6f18-870a-4cf95d479851
1f0fccb3-4855-6fe0-870a-4cf95d479851
1f0fccb3-4856-6094-870a-4cf95d479851
1f0fccb3-4856-6148-870a-4cf95d479851
1f0fccb3-4856-6206-870a-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)

01083224-57a5-406b-abfc-a9011e82567c
f4782904-85eb-4582-85ca-8831e4dd4a18
cabf58a4-c5b0-4afb-a3f6-3fc447251723
2a87fac0-c7b0-4580-8a7f-597aea32b090
6d6faa2e-38c9-4ce8-a750-80ebaa99b64a
ed05e087-09cc-4120-933a-4b12d205c2b2
2fdefabb-8745-4b01-a3b1-c38a26d80be5
ff5fd527-6fdc-4ea7-a072-423e4fddd83d
a9427d25-7dc9-43c4-9cde-126837e2078a
4659c935-86c5-4d66-9bc1-9e1624012d28
1e36c3e2-1c32-4eca-b6b0-a0bee1e439ed
da3a72cc-6066-47c1-a776-f601c346b855
c1dd95c9-43ea-43e1-972b-48543f019733
60c4a166-89af-4c1f-8c87-44f83a25078f
d4bf9d53-5a31-4409-877a-078ba3167955

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)

34856724-fccb-11f0-870a-4cf95d479851
34856788-fccb-11f0-870a-4cf95d479851
348567ec-fccb-11f0-870a-4cf95d479851
34856850-fccb-11f0-870a-4cf95d479851
348568aa-fccb-11f0-870a-4cf95d479851
34856904-fccb-11f0-870a-4cf95d479851
3485695e-fccb-11f0-870a-4cf95d479851
348569cc-fccb-11f0-870a-4cf95d479851
34856a30-fccb-11f0-870a-4cf95d479851
34856a8a-fccb-11f0-870a-4cf95d479851
34856aee-fccb-11f0-870a-4cf95d479851
34856b52-fccb-11f0-870a-4cf95d479851
34856bac-fccb-11f0-870a-4cf95d479851
34856c06-fccb-11f0-870a-4cf95d479851
34856c6a-fccb-11f0-870a-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)

6df4d10d-0f01-8d01-87ea-5ce32bd83b97
8215d20d-0f01-8d01-87ea-5ce32bd83b97
86d1d30d-0f01-8d01-87ea-5ce32bd83b97
16b6d40d-0f01-8d01-87ea-5ce32bd83b97
7adcd50d-0f01-8d01-87ea-5ce32bd83b97
d2ded60d-0f01-8d01-87ea-5ce32bd83b97
4ec4d80d-0f01-8d01-87ea-5ce32bd83b97
cb97d90d-0f01-8d01-87ea-5ce32bd83b97
4f4bda0d-0f01-8d01-87ea-5ce32bd83b97
259fdb0d-0f01-8d01-87ea-5ce32bd83b97
02fbdc0d-0f01-8d01-87ea-5ce32bd83b97
aa65dd0d-0f01-8d01-87ea-5ce32bd83b97
3a54de0d-0f01-8d01-87ea-5ce32bd83b97
bee4df0d-0f01-8d01-87ea-5ce32bd83b97
c793e00d-0f01-8d01-87ea-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: