In context of (Human) Necessities in Brno, a peculiar patent was developed. The author inferred an algorithm to determine a hypothetical degree of companionship between two living organisms. The formula takes into consideration and crosses different variables such as body mass and average lifespan of the two beings we want to calculate the value for. A sort of interdisciplinary approach into sociobiology, the psychology of the empathy and the human-animal (pet) relations opened a research field that allowed the author to present his work about the companionship compatibility index (CCI).