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)

019ad1c1-2f39-78ad-b962-1c49487d065c
019ad1c1-2f39-7a4a-8f56-ef1dec9dce65
019ad1c1-2f39-7b8e-b33a-226b2b31ef37
019ad1c1-2f39-7cad-9c55-3e02d9306433
019ad1c1-2f39-7dc7-8e70-f9108e4835dd
019ad1c1-2f39-7ede-8543-807ae138bda0
019ad1c1-2f39-7ff4-a919-fda05f52d10f
019ad1c1-2f3a-710b-a8a5-e796c0e7bf97
019ad1c1-2f3a-7225-848d-c4e5dd46f285
019ad1c1-2f3a-733c-906d-9003110083e7
019ad1c1-2f3a-7457-9a9e-05f08d6ab527
019ad1c1-2f3a-756d-b11a-1b8943052866
019ad1c1-2f3a-7688-a14f-4918d67bc32d
019ad1c1-2f3a-77a2-8c33-5b5e6326d2ff
019ad1c1-2f3a-78ea-8f2f-16219c6b8be0

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)

1f0cd739-dc62-6372-a43f-4cf95d479851
1f0cd739-dc62-6502-a43f-4cf95d479851
1f0cd739-dc62-65e8-a43f-4cf95d479851
1f0cd739-dc62-66b0-a43f-4cf95d479851
1f0cd739-dc62-676e-a43f-4cf95d479851
1f0cd739-dc62-6836-a43f-4cf95d479851
1f0cd739-dc62-68ea-a43f-4cf95d479851
1f0cd739-dc62-69a8-a43f-4cf95d479851
1f0cd739-dc62-6a5c-a43f-4cf95d479851
1f0cd739-dc62-6b1a-a43f-4cf95d479851
1f0cd739-dc62-6c5a-a43f-4cf95d479851
1f0cd739-dc62-6d22-a43f-4cf95d479851
1f0cd739-dc62-6de0-a43f-4cf95d479851
1f0cd739-dc62-6ea8-a43f-4cf95d479851
1f0cd739-dc62-6f70-a43f-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)

d924160b-8a51-4449-9110-c919d62e5c66
72229645-d31f-4aaa-9f3f-2070f4244063
c5ad4b6f-7b5a-466c-aa94-e6dc45758475
09dcc2d7-d167-4272-96a2-29b18cc9a724
3bf0197f-2d43-4798-ad27-3c2ed9d43dd4
814f90f7-45b3-41ff-aa6f-3d2843f6ac9f
a94c8ac2-73f1-4e0f-bff6-714360fea1b1
170676c4-95ea-48fe-9b7a-ed3b742fe966
b7834fba-be22-4afe-8794-7cb80cbfd88d
e57a48ea-0aa0-44c9-aa8f-0b4a25840014
03ee7251-c8cb-4cac-848d-4ac3f9066c0c
451ccfe3-4e07-46a8-9243-b98daa2d7744
49564379-a0c4-4b33-8728-778556a70438
8ae4cfee-a598-4090-8f0f-979a106bc2c6
bc66f914-b329-4e9e-a225-c5f3cb0cc6ca

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)

9dc6348e-cd73-11f0-a43f-4cf95d479851
9dc634f2-cd73-11f0-a43f-4cf95d479851
9dc63556-cd73-11f0-a43f-4cf95d479851
9dc635ba-cd73-11f0-a43f-4cf95d479851
9dc63614-cd73-11f0-a43f-4cf95d479851
9dc6366e-cd73-11f0-a43f-4cf95d479851
9dc636d2-cd73-11f0-a43f-4cf95d479851
9dc6372c-cd73-11f0-a43f-4cf95d479851
9dc63790-cd73-11f0-a43f-4cf95d479851
9dc637f4-cd73-11f0-a43f-4cf95d479851
9dc63858-cd73-11f0-a43f-4cf95d479851
9dc638b2-cd73-11f0-a43f-4cf95d479851
9dc63916-cd73-11f0-a43f-4cf95d479851
9dc63970-cd73-11f0-a43f-4cf95d479851
9dc639ca-cd73-11f0-a43f-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)

e1d80b32-4b05-8d14-87e9-5ce32bd83b97
19fd0c32-4b05-8d14-87e9-5ce32bd83b97
45930d32-4b05-8d14-87e9-5ce32bd83b97
71d10e32-4b05-8d14-87e9-5ce32bd83b97
59140f32-4b05-8d14-87e9-5ce32bd83b97
edab1032-4b05-8d14-87e9-5ce32bd83b97
40a11132-4b05-8d14-87e9-5ce32bd83b97
cc321232-4b05-8d14-87e9-5ce32bd83b97
27211332-4b05-8d14-87e9-5ce32bd83b97
33171432-4b05-8d14-87e9-5ce32bd83b97
5c931532-4b05-8d14-87e9-5ce32bd83b97
d3031632-4b05-8d14-87e9-5ce32bd83b97
b7f31732-4b05-8d14-87e9-5ce32bd83b97
67541932-4b05-8d14-87e9-5ce32bd83b97
163e1a32-4b05-8d14-87e9-5ce32bd83b97

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: