How many litter boxes do I need for my cat?
Quick answer
The rule of thumb is one litter box per cat plus one extra, so a single cat should have two boxes and two cats should have three.
The full answer
Cats are both predator and prey, and they are most vulnerable while eliminating, which is why they dislike sharing a toilet and prefer a box with more than one escape route. The extra box also gives your cat a backup when one is occupied, dirty, or temporarily moved, which prevents accidents. In multi-cat households, watch for guarding, blocking, or ambushing near a box; that is resource competition, and adding boxes usually resolves it quickly.
Placement matters just as much as count. Spread the boxes around the home rather than putting them side by side, since many cats treat two adjacent boxes as a single territory. In a multi-story home, put at least one on each floor. Choose quiet, well-ventilated, easily accessible spots that are not dead ends, and keep boxes away from washing machines, dryers, and furnaces that start suddenly, as well as away from food and water bowls.
The box itself should be large, roughly one and a half times the length of your cat from nose to base of tail, and most cats prefer a large, uncovered box with low sides. Scoop at least once a day and do regular full litter changes. More boxes make it easier to keep everything clean, and a clean box is the single most effective way to prevent litter box problems.