I asked ChatGPT 3.5 about UUIDs…

what are the chances that a uuid is generated twice

The chances of a UUID being generated twice are extremely low. A UUID is a universally unique identifier, meaning that it is extremely unlikely that two UUIDs will be the same. UUIDs are generated using a combination of random numbers and other data, such as the current time and the device’s MAC address.

The resulting UUID is 128 bits long, which means there are 2¹²⁸ (3.4 x 10³⁸) possible UUIDs. This is a very large number, and it is highly unlikely that two UUIDs will be generated that are the same.

In practice, the chances of a UUID being generated twice are so low that they can be considered effectively zero.

Therefore, UUIDs are a reliable way to uniquely identify objects or entities in a computer system.

express the chance of a collision in percent

The chance of a collision (i.e., two UUIDs being generated that are the same) is effectively zero. This is because the number of possible UUIDs is so large that it is highly unlikely that two UUIDs will be generated that are the same. To put this in perspective, the probability of a collision can be expressed as a percentage by dividing the number of collisions by the total number of possible UUIDs.

Given that there are 2¹²⁸ (3.4 x 10³⁸) possible UUIDs and the probability of a collision is effectively zero, the probability of a collision can be expressed as:

collision probability = (number of collisions) / (total number of possible UUIDs)
= 0 / 2¹²⁸
= 0%

Therefore, the probability of a collision occurring is effectively zero percent.