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)

019b3aae-9b96-7f0f-ba55-b15a220d6a3b
019b3aae-9b97-70a0-8c33-0b706e41ddae
019b3aae-9b97-731f-9825-49c2ae5925f1
019b3aae-9b97-744e-849c-7ad08d2f1b76
019b3aae-9b97-756d-8713-8e2f511ea00e
019b3aae-9b97-7684-86e2-b7c9da1bd570
019b3aae-9b97-779e-9c08-b14aff1e8cb4
019b3aae-9b97-78b5-8e49-69461009ef4c
019b3aae-9b97-79d3-974b-6b85f27ebb21
019b3aae-9b97-7aee-b3e0-e64653141076
019b3aae-9b97-7b96-8cef-37dc9930391f
019b3aae-9b97-7dcf-8e33-0e418044f21d
019b3aae-9b97-7eee-b10b-1a1d95a2663d
019b3aae-9b97-700d-ae31-cc4439b9c096
019b3aae-9b98-7130-bc80-92aa58ea8eae

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)

1f0dd765-81f2-686a-bcd8-4cf95d479851
1f0dd765-81f2-69fa-bcd8-4cf95d479851
1f0dd765-81f2-6ae0-bcd8-4cf95d479851
1f0dd765-81f2-6ba8-bcd8-4cf95d479851
1f0dd765-81f2-6c70-bcd8-4cf95d479851
1f0dd765-81f2-6d2e-bcd8-4cf95d479851
1f0dd765-81f2-6dec-bcd8-4cf95d479851
1f0dd765-81f2-6eb4-bcd8-4cf95d479851
1f0dd765-81f2-6f72-bcd8-4cf95d479851
1f0dd765-81f3-63a0-bcd8-4cf95d479851
1f0dd765-81f3-6512-bcd8-4cf95d479851
1f0dd765-81f3-65e4-bcd8-4cf95d479851
1f0dd765-81f3-66ac-bcd8-4cf95d479851
1f0dd765-81f3-676a-bcd8-4cf95d479851
1f0dd765-81f3-6828-bcd8-4cf95d479851

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)

9fcbe660-eb6e-44bb-9393-eb50eac07f71
d90574f2-b129-4a3c-afcb-e40d95480200
70c8ad5a-4d20-4803-b639-7567225040a0
f31e326d-1dfd-4ce8-8b27-05e495259d87
0c5bc789-b2d9-4434-94db-afbe58ca0952
be84fa07-5188-45e3-b2b2-03957a6e1be4
ff381510-957d-41df-9365-45a919d8a716
b7742f20-d603-44f2-8917-e954bd26c122
5661ba08-fc8a-419e-9ef4-9e723db47d9a
fdec7bac-484f-42ce-8086-cf70a31f2dec
771b91d3-e358-4a97-bde7-32f6db6d3c2e
9fb605eb-fb62-4440-a8e8-ed67beb61398
a59c95dd-d4af-439a-9e07-b76f41d047b6
8bea258b-7720-4414-8cbb-4c021a08a75c
13c2fd7c-08dd-40a9-8471-4d2f6d64d6a3

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)

581f3d46-dd76-11f0-bcd8-4cf95d479851
581f3daa-dd76-11f0-bcd8-4cf95d479851
581f3e0e-dd76-11f0-bcd8-4cf95d479851
581f3e72-dd76-11f0-bcd8-4cf95d479851
581f3ed6-dd76-11f0-bcd8-4cf95d479851
581f3f3a-dd76-11f0-bcd8-4cf95d479851
581f3f94-dd76-11f0-bcd8-4cf95d479851
581f3ff8-dd76-11f0-bcd8-4cf95d479851
581f405c-dd76-11f0-bcd8-4cf95d479851
581f40b6-dd76-11f0-bcd8-4cf95d479851
581f411a-dd76-11f0-bcd8-4cf95d479851
581f417e-dd76-11f0-bcd8-4cf95d479851
581f41e2-dd76-11f0-bcd8-4cf95d479851
581f4246-dd76-11f0-bcd8-4cf95d479851
581f42aa-dd76-11f0-bcd8-4cf95d479851

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)

590f4728-c701-8216-87e9-5ce32bd83b97
141d4928-c701-8216-87e9-5ce32bd83b97
51a04a28-c701-8216-87e9-5ce32bd83b97
de904b28-c701-8216-87e9-5ce32bd83b97
8bf94c28-c701-8216-87e9-5ce32bd83b97
8b884d28-c701-8216-87e9-5ce32bd83b97
f1e34e28-c701-8216-87e9-5ce32bd83b97
f3b64f28-c701-8216-87e9-5ce32bd83b97
a3805028-c701-8216-87e9-5ce32bd83b97
db2c5128-c701-8216-87e9-5ce32bd83b97
d4c25228-c701-8216-87e9-5ce32bd83b97
32605328-c701-8216-87e9-5ce32bd83b97
d6225428-c701-8216-87e9-5ce32bd83b97
2a275528-c701-8216-87e9-5ce32bd83b97
e7075628-c701-8216-87e9-5ce32bd83b97

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

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: