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)

019d0335-a186-7b44-a0b1-2eeab4ff54a0
019d0335-a186-7d3c-a38e-eff99db1463a
019d0335-a186-7e67-b8df-8a118ae0e69a
019d0335-a186-7fc7-8be5-8d2661598a77
019d0335-a187-711b-bf0c-04ff49988bb0
019d0335-a187-726f-a2b9-0f3e996b3831
019d0335-a187-73bf-a9a1-f91dde4b01be
019d0335-a187-750f-8444-028856daba70
019d0335-a187-765f-b674-668e469df063
019d0335-a187-77a6-9dc2-5f6ba1fd5784
019d0335-a187-78f2-bc5c-d5195b40636e
019d0335-a187-7a3e-9c6b-417c3eed5452
019d0335-a187-7b86-9b12-e14832dd5efa
019d0335-a187-7cd1-ab32-44a561ab873e
019d0335-a187-7e1d-9b9d-02ff8ed4fac9

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)

1f1231f7-2771-624c-9741-4cf95d479851
1f1231f7-2771-64b8-9741-4cf95d479851
1f1231f7-2771-6652-9741-4cf95d479851
1f1231f7-2771-67ba-9741-4cf95d479851
1f1231f7-2771-692c-9741-4cf95d479851
1f1231f7-2771-6a94-9741-4cf95d479851
1f1231f7-2771-6bfc-9741-4cf95d479851
1f1231f7-2771-6d5a-9741-4cf95d479851
1f1231f7-2771-6eae-9741-4cf95d479851
1f1231f7-2772-6020-9741-4cf95d479851
1f1231f7-2772-621e-9741-4cf95d479851
1f1231f7-2772-639a-9741-4cf95d479851
1f1231f7-2772-64f8-9741-4cf95d479851
1f1231f7-2772-6660-9741-4cf95d479851
1f1231f7-2772-67be-9741-4cf95d479851

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)

534992a9-ccda-401b-848a-132eab65bc91
3e4ecada-a6a5-4f5b-9785-2e806dc9e0b3
a54fe7d2-6304-4374-8cb5-1dcd31f5f833
465a5262-68d2-408e-baae-b679e2b60fca
fde31b20-568c-432a-aa51-92c8c03d4c6c
95d3ac66-a24d-42ea-b43e-787c483259c4
5bbe4365-912b-4540-bca2-275d2d1e026c
1efeafcc-8e22-47ad-9645-97877b70c4c8
cc6e339f-7e1a-4f0b-956e-66ac18dade06
45c3c6a2-edc3-4bfc-b487-0687301b8bbf
4f5bd99c-4f92-4d03-ba76-e89dde94506b
b39baa93-a618-4f16-a558-a1bdf7d4210c
975b04a6-8866-4248-8373-061b6ce7a1a8
927f179f-9974-4058-9046-b1e243002bd2
4de7b86f-98d1-4d7a-b003-1e93e7c77302

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)

72772ee4-231f-11f1-9741-4cf95d479851
72772f84-231f-11f1-9741-4cf95d479851
72773010-231f-11f1-9741-4cf95d479851
727730a6-231f-11f1-9741-4cf95d479851
7277313c-231f-11f1-9741-4cf95d479851
727731dc-231f-11f1-9741-4cf95d479851
72773272-231f-11f1-9741-4cf95d479851
727732fe-231f-11f1-9741-4cf95d479851
72773394-231f-11f1-9741-4cf95d479851
7277342a-231f-11f1-9741-4cf95d479851
727734b6-231f-11f1-9741-4cf95d479851
7277354c-231f-11f1-9741-4cf95d479851
727735d8-231f-11f1-9741-4cf95d479851
7277366e-231f-11f1-9741-4cf95d479851
727736fa-231f-11f1-9741-4cf95d479851

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)

ff2ea83b-6d05-8d04-87ea-5ce32bd83b97
a482a93b-6d05-8d04-87ea-5ce32bd83b97
3b07aa3b-6d05-8d04-87ea-5ce32bd83b97
e4baab3b-6d05-8d04-87ea-5ce32bd83b97
ddc3ac3b-6d05-8d04-87ea-5ce32bd83b97
5885ad3b-6d05-8d04-87ea-5ce32bd83b97
35cbae3b-6d05-8d04-87ea-5ce32bd83b97
38b6af3b-6d05-8d04-87ea-5ce32bd83b97
9e1fb03b-6d05-8d04-87ea-5ce32bd83b97
6d77b13b-6d05-8d04-87ea-5ce32bd83b97
25b8b23b-6d05-8d04-87ea-5ce32bd83b97
aab9b33b-6d05-8d04-87ea-5ce32bd83b97
0138b43b-6d05-8d04-87ea-5ce32bd83b97
6fa3b53b-6d05-8d04-87ea-5ce32bd83b97
f090b63b-6d05-8d04-87ea-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: