Hello how may I help you? Hello, I have a question about cats. I am pleased to be able to assist you. What is your question? How much space is needed in an apartment for a pet cat? Cats do not need a lot of room, so a 400 square foot apartment or larger would be fine. Can I help you with anything else? Yes. Does the space needed increase if I have two cats? Yes, 2 cats would require more space. Would a 600 square foot apartment be large enough for two cats? Yes a 600 square foot apartment should be fine for 2 cats Excellent, thank you very much for your help. My pleasure to assist