Singapura cats are the smallest cat breed in the cat fancy. On my estimation, they vary in weight from between 4 to 9 pounds or 2 to 4 kg. Clearly not all Singapura’s are very small. But as the lower end of their weight scale is 4 pounds, this is about half or even less than half the average weight of an average domestic cat. Wikipedia states that the average male weighs 6 pounds but they may have taken the information from this site. Females will be slightly smaller than males.
Therefore, Singapuras are indeed small cats. I would suspect, though, that you can’t guarantee that when you adopt one of these cats that he or she will turn out to be very small because at the top end of the scale I have decided that they can attain the weight of 9 pounds which is about an average weight for a domestic cat.
You can read about the weights of all the cat breeds by clicking on this link. The largest cat breed is the Maine Coon if you exclude exotic “breeds” such as the Savannah which is indeed the largest domestic cat if you buy a first filial.
The history of this breed is interesting. Claimed to come from Singapore’s drain cats (living in the city’s drains), the breed is probably entirely created in America. Sarah Hartwell visited the place and never saw one! See more by clicking on this link.