How many litter boxes per cat?
How many litter boxes per cat you need depends on how many cats you have and how many floors your home has. This litter box calculator gives you the number, the right size and a simple cleaning schedule.
Free calculator · Based on vet sources
The n+1 rule
Give your cats one litter box each, plus one extra. So one cat needs two boxes, two cats need three, and three cats need four. If your cats use more than one floor, put at least one box on every floor, even if that means more boxes than the rule gives. Boxes side by side in one spot count as one, because a cat sees them as a single toilet area.
Litter box size
The box should be at least 1.5 times as long as your cat, measured from the nose to the base of the tail. Many boxes sold for cats are too small for an adult. A large, clear plastic storage box with a low entry cut into one side is an easy fix. Fill it with about 2–3 inches (5–7 cm) of litter so your cat can dig and cover.
Senior cats, cats with arthritis and kittens need a low side they can step over without jumping. Most cats prefer an open box without a lid, and unscented, fine-grained clumping litter.
Where to put litter boxes
- Pick quiet spots away from loud appliances and busy doorways.
- Keep boxes away from food and water bowls.
- Don’t put all the boxes in one room. Spread them around the home.
- Choose places your cat can reach easily, day and night.
Litter boxes in a multi-cat household
In a multi-cat household, one cat can block another from a box, even without an obvious fight. Place boxes in different rooms so no cat has to walk past another to reach one. Pick spots with an escape route, not dead-end corners or closets, so a cat using the box can see who is coming and leave.
How often to clean the litter box
| Task | How often |
|---|---|
| Scoop out clumps and stool | At least once a day |
| Empty, wash and refill (clumping litter) | Every 1–2 weeks |
| Empty, wash and refill (non-clumping clay) | More often, usually at least once a week |
| Top up litter | After scooping, back to 2–3 inches (5–7 cm) |
Wash boxes with warm water and a mild, unscented soap. Avoid strong-smelling cleaners, which can put cats off the box.
When litter box changes mean a vet visit
A male cat straining with little or no urine needs a vet now
This can be a urinary blockage, which can be fatal within a day or two without treatment. Go to an emergency vet if your regular vet is closed.
Call your vet soon if your cat:
- Starts peeing outside the litter box
- Goes to the box more often, or passes only small amounts
- Has blood in the urine or cries while peeing
- Makes much bigger or more clumps than usual, which can mean drinking more
- Has diarrhea or stops passing stool
Questions about litter boxes
How many litter boxes do I need for 2 cats?
Three. The usual rule is one litter box per cat plus one extra, and at least one on every floor of your home.
How big should a litter box be?
At least 1.5 times your cat’s length from nose to the base of the tail. Many boxes sold for cats are smaller than that, so a large storage box often works better.
How often should you clean the litter box?
Scoop at least once a day. With clumping litter, empty the box, wash it and refill it every 1 to 2 weeks. Non-clumping clay needs a full change more often.
Can two cats share a litter box?
Some cats will, but many won’t, and sharing is a common reason cats pee outside the box. Giving each cat its own box plus one extra, in different spots, avoids most problems.
Source: AAFP/ISFM Feline Environmental Needs Guidelines, International Cat Care and the Cornell Feline Health Center.
