How many hours a day do cats sleep?
Most adult cats sleep around 12 to 16 hours a day, and kittens and older cats can sleep even more. Much of it is light dozing rather than deep sleep.
Going deeper
Cats are built for short bursts of hunting, which takes a lot of energy, and sleeping saves it. They are also most active at dawn and dusk, which is why your cat may be wide awake at 5am.
A lot of cat sleep is light, so they can wake quickly. That's the classic half-closed-eye snooze with ears still turning toward sounds.