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)

019d6425-ff5c-7192-9d26-eed830f690c0
019d6425-ff5c-73af-ae9c-a87bbbbbd3e5
019d6425-ff5c-751b-8d1e-ec1249b6b633
019d6425-ff5c-765b-b93a-0f617779a393
019d6425-ff5c-779a-bcc0-e7d74706497b
019d6425-ff5c-78d5-b626-0ec9caff2cd3
019d6425-ff5c-7a11-a684-9e4a02296bbf
019d6425-ff5c-7b4c-a416-54e57c7adac4
019d6425-ff5c-7c88-aedb-4d6daf4df594
019d6425-ff5c-7dc3-9e9b-3d4f6ddf0574
019d6425-ff5c-7efa-a8e8-71ae1f855c28
019d6425-ff5d-7036-9774-42195ee7edaf
019d6425-ff5d-7171-87e4-06fddb1d73fd
019d6425-ff5d-72ad-a97b-921d504b16ec
019d6425-ff5d-73e8-8e8b-3173e4aa39e6

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)

1f131ea1-fc86-6ea4-a496-4cf95d479851
1f131ea1-fc87-60f2-a496-4cf95d479851
1f131ea1-fc87-626e-a496-4cf95d479851
1f131ea1-fc87-63d6-a496-4cf95d479851
1f131ea1-fc87-652a-a496-4cf95d479851
1f131ea1-fc87-6674-a496-4cf95d479851
1f131ea1-fc87-67c8-a496-4cf95d479851
1f131ea1-fc87-691c-a496-4cf95d479851
1f131ea1-fc87-6a70-a496-4cf95d479851
1f131ea1-fc87-6bba-a496-4cf95d479851
1f131ea1-fc87-6da4-a496-4cf95d479851
1f131ea1-fc87-6f02-a496-4cf95d479851
1f131ea1-fc88-604c-a496-4cf95d479851
1f131ea1-fc88-61a0-a496-4cf95d479851
1f131ea1-fc88-62ea-a496-4cf95d479851

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)

d9bef849-3e0e-4132-a4e0-6b9a89acae59
c3ca68bd-c9e4-4089-b454-efe2cd11bde4
3d848a57-1da9-4c20-a36e-7e4610b582df
747e2dd6-352c-4809-b75f-49ea7d54c820
4cd6e630-4e55-4c54-bdf2-bde037ac4e21
36cc2799-6733-44ee-a95b-f964654eedc3
4f605fa8-2129-462c-a244-c48b8561e32e
68f5a691-b59b-4572-9073-fa485259f5ab
2fa664ba-e5e4-4fc4-b690-2ba018683982
2f1cc219-19f8-4142-9030-389b01131b99
ded0611a-37f0-4c0e-b6e5-8a5274b553bb
6ed59660-fbc9-4da4-a014-bf7d30ec4c91
33d2c549-2199-4e02-af9b-eaa14b2568c5
f68e7859-2524-4810-9a40-d1a1b65ffa19
978bbc84-00be-4a58-a6cb-25a6434df334

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)

1fc889e8-31ea-11f1-a496-4cf95d479851
1fc88a7e-31ea-11f1-a496-4cf95d479851
1fc88b14-31ea-11f1-a496-4cf95d479851
1fc88baa-31ea-11f1-a496-4cf95d479851
1fc88c36-31ea-11f1-a496-4cf95d479851
1fc88cc2-31ea-11f1-a496-4cf95d479851
1fc88d58-31ea-11f1-a496-4cf95d479851
1fc88de4-31ea-11f1-a496-4cf95d479851
1fc88e70-31ea-11f1-a496-4cf95d479851
1fc88efc-31ea-11f1-a496-4cf95d479851
1fc88f92-31ea-11f1-a496-4cf95d479851
1fc89028-31ea-11f1-a496-4cf95d479851
1fc890be-31ea-11f1-a496-4cf95d479851
1fc89154-31ea-11f1-a496-4cf95d479851
1fc891e0-31ea-11f1-a496-4cf95d479851

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)

e0f50e05-7004-8006-87ea-5ce32bd83b97
b10c0f05-7004-8006-87ea-5ce32bd83b97
39871005-7004-8006-87ea-5ce32bd83b97
073b1105-7004-8006-87ea-5ce32bd83b97
2f031205-7004-8006-87ea-5ce32bd83b97
d7fd1305-7004-8006-87ea-5ce32bd83b97
e1981405-7004-8006-87ea-5ce32bd83b97
eff31505-7004-8006-87ea-5ce32bd83b97
1e6a1605-7004-8006-87ea-5ce32bd83b97
bcdb1705-7004-8006-87ea-5ce32bd83b97
0f2a1805-7004-8006-87ea-5ce32bd83b97
5fd01905-7004-8006-87ea-5ce32bd83b97
fc151a05-7004-8006-87ea-5ce32bd83b97
a9be1b05-7004-8006-87ea-5ce32bd83b97
540d1c05-7004-8006-87ea-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: