Cat Litter Box Liners: Sizing and Setup for Indoor Season

Scheduled September 2026 · Pet N Pet Editorial

We sell litter box liners, so we will start with the inconvenient part. The ASPCA's guidance on litter box problems says "most cats don't like box liners or lids on their boxes," and when a cat is eliminating outside the box its advice is to "remove covers and liners from all litter boxes" (ASPCA). That is worth knowing before you buy anything, including from us.

What that guidance does not say is that liners never work. It says they are the first thing to pull when a cat is already having a problem. Those are different statements, and the gap between them is mostly about size.

Do cats actually dislike liners?

Many do, and the reasons are physical rather than mysterious. Two failure modes come up consistently in feline behaviour guidance: a cat's claws catch in the plastic while it digs, and the liner forms pockets and folds that trap urine, which makes the odour problem worse rather than better.

Both of those are worth taking seriously because digging is not optional behaviour. Veterinary guidance is explicit that litter should be provided "at a sufficient depth to allow burying of faeces and urine" (2022 ISFM/AAFP guidelines), and Ohio State's Indoor Pet Initiative puts the working figure at "enough litter to permit the cat to scratch and bury waste (usually about 2 inches deep)" (Ohio State University Indoor Pet Initiative).

UNIQUE INSIGHT

Put those two facts next to each other and the liner problem resolves into something you can actually fix. A liner interferes with burying only where the cat's claws can reach it which means the real variable is not "liner or no liner," it is how much litter sits between the claw and the plastic, and whether the liner lies flat enough to stay out of the way. An undersized liner stretched tight across the bottom of a box, with a thin scatter of litter over it, is the worst possible version. A generously sized liner tucked over the rim with a full 2 inches of litter on top is a materially different object from the cat's point of view. Most "cats hate liners" advice is describing the first setup, because the first setup is what a standard liner in a large box produces.

What size should the box be?

Bigger than almost everything sold as a litter box. The veterinary benchmark is proportional to the cat: litter boxes "should be 1.5 times the length of the cat (from nose to base of tail) in size" (2022 ISFM/AAFP Cat Friendly Veterinary Environment Guidelines).

Ohio State frames the same requirement functionally: the box "should be large enough for your cat to stand up (on all fours) and turn around in," and notes that "cats generally prefer large, uncovered litter boxes" (Indoor Pet Initiative). The ASPCA agrees that "the majority of cats prefer large boxes that they can enter easily."

Work it in that order and the liner question answers itself. Measure the cat, size the box at 1.5 times that length, then buy a liner that clears the box on every side with enough slack to fold over the rim. A liner that only just fits the base is the one that pulls taut, forms pockets and catches claws. Our jumbo cat litter box liners are sized for that third step, because a correctly sized box for most adult cats is larger than the boxes standard liners were cut for.

How do you set up a lined box a cat will still use?

Five things, and none of them are about the liner brand.

Two additions specific to running a liner. Fold the excess over the outside rim rather than tucking it inside, so there is no loose edge inside the box for a claw to find. And spread the litter to full depth before the cat's first use, not after the first experience of a newly lined box is the one that decides whether it gets used.

PERSONAL EXPERIENCE

The tell that a liner is not working is not a mess on the floor, it is claw marks. If you lift the litter at change time and find punctures or drag lines in the plastic, the cat is reaching it while digging. That is your signal to go up a liner size or add litter depth, and it usually arrives before the cat starts avoiding the box.

What changes for indoor season?

Volume and ventilation, mostly. Autumn and winter move cats indoors and keep them there, which raises box use in the same weeks the windows close.

Two adjustments follow. Placement matters more when the house is shut: Ohio State advises keeping boxes "away from appliances or air ducts," giving the cat privacy without cornering it, and putting a box "on each level" of a multi-storey home. And the weekly full change stops being optional, since the odour that was tolerable with airflow will not be.

Skip the scented litter, tempting as it is in a closed house. Ohio State is direct that "many cats are put off by the odor of scented or deodorant litters." Fixing odour by making the box less attractive trades a smell for a house-soiling problem.

For the dog side of the same seasonal shift, our pee pads cover indoor toileting, and dog wipes handle what comes in on paws.

When should you skip the liner?

Three cases, stated plainly.

If the cat is already avoiding the box. Follow the ASPCA's sequence and remove covers and liners first, before you change anything else. Reintroduce a liner later if you want, once the cat is reliably using the box again.

If you find claw damage that persists after you have sized up. Some cats dig hard enough that no amount of litter depth keeps them off the plastic. That cat has told you its preference; take the liner out.

If the liner does not fit the box properly and you cannot get one that does. A taut, undersized liner is worse than no liner. It produces both documented failure modes at once claw contact and urine-trapping folds while saving you very little cleaning time.

Liners earn their place in the opposite conditions: a correctly oversized box, a cat that scratches normally rather than obsessively, full-depth litter, and a household where the weekly full change is the job you are actually trying to make faster. That is a real set of houses. It is just not all of them, and a brand that sells liners should say so.

INTERNAL LINK cat litter liner range and sizes → /collections/cat-litter-liners

Frequently Asked Questions

Are litter box liners bad for cats?

Not inherently, but the ASPCA notes that "most cats don't like box liners or lids on their boxes" and advises removing both when a cat stops using the box. The documented problems are mechanical claws catching in plastic while digging, and folds trapping urine. Both get worse with an undersized liner and better with a generously sized one under full-depth litter.

What size litter box do I need?

Measure your cat from nose to the base of the tail and multiply by 1.5. That is the veterinary benchmark in the 2022 ISFM/AAFP guidelines. As a functional check, the box should let the cat stand on all fours and turn around comfortably. Most boxes sold as standard fall short of this for adult cats, which is why liner sizing so often mismatches.

How many litter boxes should I have?

One per cat plus one. Ohio State's Indoor Pet Initiative calls it "the Golden Rule," and the ASPCA gives the same figure. In a multi-storey home, put a box on each level rather than clustering them.

How deep should the litter be?

About 2 inches. Ohio State's figure is "enough litter to permit the cat to scratch and bury waste (usually about 2 inches deep)"; the ASPCA suggests one to two inches rather than three to four. With a liner in place, depth is doing double duty it also keeps claws away from the plastic.

How often should I change a lined litter box?

Scoop daily and do a full change weekly, washing the box with mild dish detergent, unscented soap, baking soda or no soap. Avoid ammonia-based cleaners. A liner makes the weekly change faster; it does not extend the interval.

Should I use a covered litter box with a liner?

Generally no on the cover. Ohio State reports that cats "generally prefer large, uncovered litter boxes," and covers concentrate odour. Combining a cover and a liner stacks two of the things the ASPCA recommends removing first when a cat starts having problems.

SOURCES & CITATIONS

ASPCA "Litter Box Problems," retrieved 2026-09-01 https://www.aspca.org/pet-care/cat-care/common-cat-behavior-issues/litter-box-problems

Ohio State University College of Veterinary Medicine, Indoor Pet Initiative "Litter Boxes," retrieved 2026-09-01 https://indoorpet.osu.edu/cats/basic-indoor-cat-needs/litter-boxes

Samantha Taylor, Kelly St Denis, Sarah Collins, et al. "2022 ISFM/AAFP Cat Friendly Veterinary Environment Guidelines," Journal of Feline Medicine and Surgery 24(11), 2022, pp. 1133–1163, doi:10.1177/1098612X221128763, retrieved 2026-09-01 https://pmc.ncbi.nlm.nih.gov/articles/PMC10845436/

American Pet Products Association "U.S. Pet Industry Reaches $158 Billion in 2025, Poised for Continued Growth in 2026," 26 March 2026, retrieved 2026-09-01 https://americanpetproducts.org/news/u.s.-pet-industry-reaches-158-billion-in-2025-poised-for-continued-growth-in-2026