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)

019f4678-2236-7019-97c8-0c058e31dc4b
019f4678-2237-7257-a7f7-dd41187b6f8b
019f4678-2237-73dc-94db-873537f1b672
019f4678-2237-753c-b0d0-1fdf4afec78f
019f4678-2237-7684-bc35-b3f7f81afd18
019f4678-2237-77cb-bb9b-a2e73df4375d
019f4678-2237-790b-9cee-cd15b58b54cf
019f4678-2237-7a4a-9a60-0415ea23a07d
019f4678-2237-7b8a-ac01-a0e5847e9ad1
019f4678-2237-7cc9-aae6-bcec36851936
019f4678-2237-7e09-9727-0a334354adca
019f4678-2237-7f44-8925-775631f14029
019f4678-2238-707f-9e21-311250261662
019f4678-2238-71bf-98a8-71a633bd016d
019f4678-2238-72fe-8100-56bfd65488e6

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)

1f17b82c-839f-6814-861b-4cf95d479851
1f17b82c-839f-6ab2-861b-4cf95d479851
1f17b82c-839f-6c2e-861b-4cf95d479851
1f17b82c-839f-6d8c-861b-4cf95d479851
1f17b82c-839f-6ee0-861b-4cf95d479851
1f17b82c-83a0-602a-861b-4cf95d479851
1f17b82c-83a0-6174-861b-4cf95d479851
1f17b82c-83a0-62be-861b-4cf95d479851
1f17b82c-83a0-63fe-861b-4cf95d479851
1f17b82c-83a0-6552-861b-4cf95d479851
1f17b82c-83a0-6750-861b-4cf95d479851
1f17b82c-83a0-68ae-861b-4cf95d479851
1f17b82c-83a0-69ee-861b-4cf95d479851
1f17b82c-83a0-6b2e-861b-4cf95d479851
1f17b82c-83a0-6c78-861b-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)

c83a0de0-7b82-11f1-861b-4cf95d479851
c83a0e76-7b82-11f1-861b-4cf95d479851
c83a0f0c-7b82-11f1-861b-4cf95d479851
c83a0f98-7b82-11f1-861b-4cf95d479851
c83a1024-7b82-11f1-861b-4cf95d479851
c83a10ba-7b82-11f1-861b-4cf95d479851
c83a1146-7b82-11f1-861b-4cf95d479851
c83a11d2-7b82-11f1-861b-4cf95d479851
c83a1268-7b82-11f1-861b-4cf95d479851
c83a12f4-7b82-11f1-861b-4cf95d479851
c83a138a-7b82-11f1-861b-4cf95d479851
c83a142a-7b82-11f1-861b-4cf95d479851
c83a14ca-7b82-11f1-861b-4cf95d479851
c83a1574-7b82-11f1-861b-4cf95d479851
c83a1614-7b82-11f1-861b-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)

69bc0a2e-8202-8e0b-87ea-5ce32bd83b97
8fa20b2e-8202-8e0b-87ea-5ce32bd83b97
0ca10d2e-8202-8e0b-87ea-5ce32bd83b97
afe00e2e-8202-8e0b-87ea-5ce32bd83b97
ca6f0f2e-8202-8e0b-87ea-5ce32bd83b97
f966102e-8202-8e0b-87ea-5ce32bd83b97
6da6112e-8202-8e0b-87ea-5ce32bd83b97
2325122e-8202-8e0b-87ea-5ce32bd83b97
02b4132e-8202-8e0b-87ea-5ce32bd83b97
e1eb142e-8202-8e0b-87ea-5ce32bd83b97
2e34152e-8202-8e0b-87ea-5ce32bd83b97
5acd162e-8202-8e0b-87ea-5ce32bd83b97
ff05172e-8202-8e0b-87ea-5ce32bd83b97
459d182e-8202-8e0b-87ea-5ce32bd83b97
a009192e-8202-8e0b-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)

4e2f3d37-b2f3-493e-a2fe-1c49dc73a73d
b2a644fc-3b07-4666-b76f-d37a58df8cf7
c7389791-14b3-41a1-b74d-cfb787de6fa1
7840a41f-5339-43a3-8923-1eaa1f297bcb
531457f0-58dd-465b-85e1-3413fa399f2d
d1895cef-66c0-46b6-9f6b-6e30885791bc
679109b2-518f-425f-929f-8deb53c27b29
fd55227c-92fc-4667-9676-f5fb1b878c40
94421929-8412-4686-8bc9-5042a08b8bf3
5215b4fe-2822-40ba-9f32-8a61895098ab
189f0c85-6338-40da-9d50-567ded57cee3
f4e09501-a00c-4d49-8687-265b072bbf92
b362ae09-5c56-450f-b0da-9fb43b59a456
5a96287d-2566-4b86-ab28-2aecfee105ae
c3157d03-aea5-4dec-be1b-6376efb56346

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: