As a cat owner, you probably wonder whether your cat is sleeping too much or too little. For some, it can seem like their cat spends all day lazing around. For others, their hyperactive cat may never seem to settle down. While the amount of time a cat will sleep in a day depends on the individual, the age of the cat greatly affects how much they sleep. This changes particularly for kittens, adult cats and senior cats. For example, a kitten will sleep an average of 20 hours per day, while an adult cat only sleeps about 16.