This is such a great question and one I wish I could answer with a factual, straight forward answer. The tricky part is that, similar to humans where we look at our BMIs [Body Mass Index], which are based on age, height, etc., there are many factors to consider. My rule of thumb is that I want to be able to feel over top of their rib cage and not have any difficulty feeling for each individual rib. I also want to be able to see a waist when I look at them from a bird’s eye view. If you’re looking for a hard number, most cats sit somewhere between 7-15 pounds. One of my cats is 15 pounds and he’s a little skinny. I have another who’s 7 pounds and she’s perfect. I’ve never met a 20-pound cat who wasn’t overweight.