Cats can sleep for about 4 hours at a time. If they are kittens, the sleeping time will be longer. Normal adult cats need to sleep about 16 hours a day, and kittens need to sleep about 20 hours. However, cats only have about 5 hours of deep sleep a day, and the rest of the time is light sleep. Because cats are nocturnal animals, they need to rest to recharge their batteries.