The most common reason: marking territory and covering waste

Your cat scratches the litter box sides for the same reason it scratches the bottom — to bury waste and mark territory. Cats have scent glands in their paws, so scratching leaves a chemical signal that says "this is my bathroom." The sides get scratched when your cat is trying to cover waste that's piled higher than usual, when the box is too small to dig properly, or when the litter itself is too shallow to allow a full digging motion.

This is normal cat behavior, not a sign of stress or illness. A cat that scratches the sides is doing exactly what it evolved to do: hide evidence of its presence from predators and claim the space as its own. The scratching at the sides happens most often when the litter depth is less than 2 to 3 inches, because the cat can't dig down far enough and compensates by scratching upward.

Key Takeaways

  • Side scratching is normal territorial and waste-covering behavior, not a behavioral problem.
  • Litter that is too shallow (under 2 inches) forces cats to scratch the sides instead of digging down.
  • A box that is too small prevents your cat from turning around and digging properly, leading to side scratching.
  • Cats with arthritis or joint pain may scratch the sides because digging down hurts, so they scratch around the edges instead.
  • Some cats scratch the sides to signal that the box is dirty and needs cleaning.

Litter depth and box size matter more than you think

The depth of litter in the box directly affects where your cat scratches. If you're filling the box with only 1 inch of litter, your cat cannot dig down to bury waste properly. Instead, it will scratch the sides and corners, trying to create a deeper hole. The solution is straightforward: fill the box with 2 to 3 inches of litter. This gives your cat enough material to dig down, cover waste, and scratch without hitting the bottom of the box.

Box size is equally important. A box should be at least 1.5 times the length of your cat's body. If the box is too small, your cat cannot turn around, squat comfortably, or dig in a natural position. When confined, cats often scratch the sides in frustration or as a way to signal that the space doesn't work for them. A larger box — or a second box in a different location — often stops side scratching when ready.

Pain or discomfort can change scratching patterns

If your cat suddenly starts scratching the sides more than usual, or scratches only the sides and avoids digging down, pain may be the reason. Cats with arthritis, hip dysplasia, or other joint problems find it painful to crouch low and dig. Instead, they scratch at the sides and edges of the box, which requires less bending and puts less weight on their back legs.

Older cats and overweight cats are most likely to show this pattern. If your cat is also moving more slowly, hesitating before entering the box, or spending longer in the box than before, a veterinary checkup is worth scheduling. Pain-related changes in litter box behavior often come with other signs — limping, reluctance to jump, or stiffness after rest.

Dirty litter triggers more scratching

Cats that scratch the sides frequently may be signaling that the box is too dirty. When litter becomes compacted, wet, or filled with clumps, it's harder to dig in. Your cat will scratch the sides as a way of saying the box needs attention. Some cats also scratch more when they're trying to find a clean spot within a dirty box.

Scooping once or twice daily and doing a full litter change weekly usually reduces unnecessary side scratching. If you notice your cat scratching more on days when you haven't scooped, the litter condition is likely the issue. Some cats are also sensitive to litter type — switching to a finer or coarser texture can change scratching behavior.

Litter type affects how cats dig and scratch

Different litter textures encourage different scratching patterns. Clay-based litter that clumps well allows cats to dig and bury waste easily, so they scratch less at the sides. Lightweight or crystal litter can be harder to dig in, causing cats to scratch the sides more as they try to move material around.

If you've recently changed litter brands or types, that change may explain increased side scratching. Some cats also scratch the sides more with unscented litter because they can't track the scent as easily and feel less confident that waste is covered. Switching back to your previous litter, or trying a clumping clay litter if you haven't used one, can reduce the behavior.

Medical issues that show up as litter box changes

Rarely, changes in scratching behavior point to a medical problem. Cats with urinary tract infections, digestive issues, or other conditions sometimes spend more time in the litter box and scratch more frequently. If your cat is also urinating or defecating more often, straining, or showing blood in urine or stool, contact a veterinarian.

Hyperthyroidism and diabetes can also increase litter box visits and change bathroom behavior. These conditions are common in older cats and show up as increased thirst, weight loss, or changes in appetite alongside litter box changes. Side scratching alone is not a sign of illness, but side scratching combined with other changes warrants a checkup.

When to add a second litter box

The standard rule is one box per cat plus one extra. If you have one cat and one box, adding a second box in a different room or on a different floor can reduce side scratching. Some cats scratch the sides because they feel trapped or because the box location doesn't suit them — a second box gives them a choice.

Multi-cat households especially benefit from extra boxes. Cats that feel crowded out or anxious about sharing a box will scratch the sides more. Placing boxes in separate locations — one upstairs, one downstairs, one in a quiet corner — gives each cat a space that feels safe and private.

Frequently Asked Questions

Is my cat scratching the sides because it's stressed?

Side scratching is normal behavior, not a sign of stress on its own. However, if your cat is also hiding, not eating, or avoiding the box entirely, stress may be involved. Check that the box is large enough, the litter is deep enough, and the location is quiet and away from food and water bowls.

Should I use a covered litter box to stop the scratching?

Covered boxes often make side scratching worse because they reduce space and make it harder for cats to dig naturally. If your cat is scratching the sides, an open box or a box with a removable top is usually better. Covered boxes also trap odor and moisture, which some cats dislike.

Does side scratching mean the litter is too wet?

Wet or clumpy litter can trigger more scratching, but it's not the only cause. Check that you're scooping daily and that the litter depth is 2 to 3 inches. If the box still smells strongly of ammonia or feels damp, a full litter change and more frequent scooping will help.

Can I train my cat to stop scratching the sides?

You can't train away normal scratching behavior, but you can remove the reasons for it. Increase litter depth, use a larger box, scoop more often, and try a different litter type. Once the box meets your cat's needs, side scratching usually decreases on its own.

What if my cat scratches the sides but uses the box normally otherwise?

If your cat is using the box, covering waste, and not having accidents, side scratching is just a quirk. Some cats are more vigorous diggers than others. As long as litter isn't ending up on the floor and your cat seems comfortable, no change is needed.