UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

01a06315-c3c1-7e73-8d02-67785fed2657
01a06315-c3c2-7021-a39d-aa8712744a7d
01a06315-c3c2-715d-a7f9-29af7872fdd3
01a06315-c3c2-7277-b13b-75bbe04ce2a7
01a06315-c3c2-738a-952e-1e5bf5c09a01
01a06315-c3c2-7498-a99c-dd2bb92fd861
01a06315-c3c2-75aa-a080-e532d50bed55
01a06315-c3c2-76b9-8566-4f46328b5849
01a06315-c3c2-77cf-bbbc-bedd12fd8a1b
01a06315-c3c2-78e2-84aa-b213f88fb190
01a06315-c3c2-79f4-a877-b08eda448efd
01a06315-c3c2-7b07-ada2-8261d5853849
01a06315-c3c2-7c19-abe3-abf8e871bea4
01a06315-c3c2-7d2c-9391-294e3a8a622a
01a06315-c3c2-7e3a-bf45-8c69b85728a2

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)

1f1a6f09-5b03-6270-ad5a-4cf95d479851
1f1a6f09-5b03-6432-ad5a-4cf95d479851
1f1a6f09-5b03-6518-ad5a-4cf95d479851
1f1a6f09-5b03-65e0-ad5a-4cf95d479851
1f1a6f09-5b03-66a8-ad5a-4cf95d479851
1f1a6f09-5b03-6766-ad5a-4cf95d479851
1f1a6f09-5b03-6824-ad5a-4cf95d479851
1f1a6f09-5b03-68e2-ad5a-4cf95d479851
1f1a6f09-5b03-6996-ad5a-4cf95d479851
1f1a6f09-5b03-6a54-ad5a-4cf95d479851
1f1a6f09-5b03-6ba8-ad5a-4cf95d479851
1f1a6f09-5b03-6c70-ad5a-4cf95d479851
1f1a6f09-5b03-6d2e-ad5a-4cf95d479851
1f1a6f09-5b03-6dec-ad5a-4cf95d479851
1f1a6f09-5b03-6eaa-ad5a-4cf95d479851

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)

95b03f72-a6f0-11f1-ad5a-4cf95d479851
95b03fd6-a6f0-11f1-ad5a-4cf95d479851
95b04030-a6f0-11f1-ad5a-4cf95d479851
95b0409e-a6f0-11f1-ad5a-4cf95d479851
95b040f8-a6f0-11f1-ad5a-4cf95d479851
95b0415c-a6f0-11f1-ad5a-4cf95d479851
95b041c0-a6f0-11f1-ad5a-4cf95d479851
95b0421a-a6f0-11f1-ad5a-4cf95d479851
95b04274-a6f0-11f1-ad5a-4cf95d479851
95b042d8-a6f0-11f1-ad5a-4cf95d479851
95b04332-a6f0-11f1-ad5a-4cf95d479851
95b04396-a6f0-11f1-ad5a-4cf95d479851
95b043f0-a6f0-11f1-ad5a-4cf95d479851
95b04454-a6f0-11f1-ad5a-4cf95d479851
95b044b8-a6f0-11f1-ad5a-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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

757ce305-0304-850f-87ea-5ce32bd83b97
3725e405-0304-850f-87ea-5ce32bd83b97
17b5e505-0304-850f-87ea-5ce32bd83b97
51cae605-0304-850f-87ea-5ce32bd83b97
1bdde805-0304-850f-87ea-5ce32bd83b97
de8ae905-0304-850f-87ea-5ce32bd83b97
204cea05-0304-850f-87ea-5ce32bd83b97
92a7eb05-0304-850f-87ea-5ce32bd83b97
1f18ec05-0304-850f-87ea-5ce32bd83b97
b68eed05-0304-850f-87ea-5ce32bd83b97
6d7aee05-0304-850f-87ea-5ce32bd83b97
1201ef05-0304-850f-87ea-5ce32bd83b97
5347f005-0304-850f-87ea-5ce32bd83b97
40c1f105-0304-850f-87ea-5ce32bd83b97
19e0f205-0304-850f-87ea-5ce32bd83b97

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)

7936cfa2-8f28-4b3e-8c2c-db476c2a824a
5d15620b-7ad6-426c-815f-f8f9a6a2bcc9
02c46b05-6708-45d6-b52c-f5c4ffac9a51
ae88146c-6ac0-49f2-a854-f5b75dad068e
8dd55038-a86c-4ab8-964b-8406c797dab4
a2421f3b-b129-49f9-9455-39a4651e7b53
4b244606-807f-4e26-b666-6b35947be484
90bc6703-d399-4bdf-8f27-2080568f8691
036b68bd-98a2-4d04-b676-aa7eebc17a81
74fdc35f-6c0f-4218-9242-2fb93b4dac0a
09c73e56-717c-45d9-b2d6-aa1d29efa058
d2df2678-ef17-4278-bc80-23719c916b76
bce72799-cee8-4df6-b5d8-0be682509d82
029d197c-6df3-4d8a-b045-cf7fa88f3711
1564b932-d16e-4d6c-815e-c6ef97084677

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: