Hello how may I help you? How much space do I need in an apartment for a pet cat? What kind of cat is it? She is siomese. You need about 600 sq feet for that kind of cat. That isn't very much is it? Not really. The cat manages itself very well. So they don't really need a ton of space I take it? No they don't. They often times just stick to the same locations and can adapt to any situation. That's great. We very much appreciate the info. You're welcome!