Is 6 pounds a healthy weight for a full grown cat?

It depends on the bone structure of the cat. A domestic cat can weigh about 6 to 10 pounds, on average, depending on the size of its bones. If you can see your cat's ribs easily and without having to touch the cat's side, it is probably underweight. If it is underweight, it may also be underactive, due to lack of energy. If he or she is not eating regularly, you might need to take the cat to a veterinarian. There could be something as simple as a hairball causing the problem, or something more serious. See the Related Link below for a visual guide to your cat's weight.