Best Cat Litter Boxes (2026): Size, Covered vs Open, and Self-Cleaning

For most adult cats, the best litter box is a big, open one: the IRIS USA XX-Large High Sided is 30 inches long, which meets the American Association of Feline Practitioners' advice that a box be at least one and a half times the cat's length. Add a covered or top-entry box only if your cat accepts it, give kittens and older cats low sides, and treat a self-cleaning box as an optional extra with rules of its own.

How we chose: we did not test these boxes; we checked each listing's dimensions against the AAFP and Cornell guidance below, and kept only boxes sold by Amazon.com or the brand's own store and in stock on September 28, 2026.

Seven litter boxes side by side

Prices are Amazon's, as of the time shown, and subject to change. Details

How many boxes, and how big

Start with the count. Cornell's Feline Health Center, in its page on house soiling, says: "Provide as many boxes as there are cats in the house, plus one." The ASPCA gives the same rule, and so does the AAFP. Two cats means three boxes, ideally not side by side: the AAFP's client handout says boxes "should be placed in at least 2 different locations."

Then size. The AAFP's Feline Behavior Guidelines say "cats prefer litter boxes that are at least 1.5 times the length of their bodies" and that "many commercial litter boxes are too small for larger cats." The same handout suggests sweater storage boxes, cement mixing tubs and small dog litter pans as alternatives. Cornell puts it more briefly: "Larger cats need bigger boxes."

To use the rule, measure your cat from nose to the base of the tail and multiply by 1.5. A cat that measures 18 inches wants a box about 27 inches long. By that math the IRIS XX-Large (30 in) suits most adult cats, the Nature's Miracle hood (25 in) suits an average cat, and the Amazon Basics box (19 in) suits a smaller one. The Modkat Top-Entry is about 16 inches square per its listing, so it suits a smaller cat. For the PetSafe ScoopFree, weight is the limit: PetSafe's own manual says it is "best for cats under 15 lb."

Litter depth matters too. The ASPCA says "most cats like a shallow bed of litter" and to use "one to two inches of litter rather than three to four inches." Our cat litter guide compares clay, silica, pine, wheat and tofu litters.

Covered or open?

Cornell is direct: "Most cats prefer an uncovered box that lets odors escape and allows a 360-degree view of their surroundings." The ASPCA adds that "most cats don't like box liners or lids on their boxes." A hood keeps the smell away from you, which is the point, but it also keeps it inside with the cat.

That does not make a hooded box wrong. Some cats spray high or kick litter hard, and a hood or a high back stops both. If your cat already uses a covered box without trouble, the Nature's Miracle Hooded Flip Top has a charcoal filter and a front that flips up for scooping. If you are switching a cat from open to covered, try it next to the old box, not instead of it.

Top-entry boxes solve two different problems: tracked litter and a dog that raids the box. The IRIS Large Top Entry has a grooved lid to catch litter, and IRIS says the top entry keeps other pets such as dogs out. The Modkat Top-Entry uses its lid as a walk-off mat and swivels open for scooping. Both ask the cat to jump in and climb out. The ASPCA warns that "boxes that have sides that are too high or have a top-side opening might make it difficult for your cat to enter or leave the box," so skip top entry for a kitten, a senior or a cat with stiff joints.

Boxes for kittens and older cats

Cornell says "kittens and elderly cats need boxes with low sides," and the AAFP's guidelines tell owners of young kittens to "provide litter boxes with low sides for easy entry." For a kitten's first weeks, the Petmate Basic Open Pan, Small has 3.5 inch sides, and Petmate says it suits small cats or kittens. Move up to a full-size box as the kitten grows; our new kitten checklist covers the rest of the first-day list.

For an older cat, the AAFP says more and bigger boxes, cleaned often, help prevent accidents caused by dirty boxes, "decreased ability to get to or into the box," and disorientation. It also suggests night lights for cats with failing vision. The Amazon Basics box has a lowered front that its listing says helps older and large cats, and the IRIS XX-Large has a 6.5 inch entrance in a 14 inch wall.

A cat that suddenly stops using its box may be ill, not fussy. Cornell says "any medical condition that interferes with a cat's normal urination or defecation behavior can cause litter box problems," and the ASPCA lists urinary tract infection, interstitial cystitis and bladder stones among the causes. If the change is sudden, or your cat strains or cries in the box, ask your vet (more on that). Clean any accidents with an enzyme product; our enzyme cleaner guide explains why.

Self-cleaning boxes: the rules makers publish

A self-cleaning box saves scooping, not judgment. The ASPCA says "many cats accept them readily," but "if you're using a self-cleaning litter box and your cat starts eliminating outside the box, try switching to a traditional type of litter box." You also lose the daily look at the clumps that tells you when something has changed, so check the app or the waste drawer.

The makers set age and weight limits because their sensors need them:

• PetSafe ScoopFree. The Crystal Pro manual says: "If your kitten is under 6 months of age, leave the unit UNPLUGGED and scoop waste until kitten is 6 months old." It rakes "20 minutes after your cat leaves the litter box" and is "best for cats under 15 lb." PetSafe's setup guide repeats the 6 month rule.
• Whisker Litter-Robot 4. Whisker's FAQ says its SmartScale "will not recognize kittens that weigh less than 3 lbs (1.3 kg)," so those kittens "can use Litter-Robot 4, but not in automatic mode."

So a kitten under the maker's minimum should not use a self-cleaning box in automatic mode. Leave it switched off and scoop by hand until the kitten passes the age or weight the maker names.

We kept the PetSafe ScoopFree Crystal Pro Legacy because Amazon.com sells it. It uses disposable trays of crystal litter, and PetSafe says a tray keeps the box fresh for up to 30 days. We left out the Litter-Robot 4: on September 28, 2026 its Amazon listings were sold by Spreetail, not by Amazon.com or Whisker.

Recalls

None of these brands appears on our pet product recall page, which tracks FDA and CPSC pet recalls from 2024 onward, and a search of the CPSC recall database on September 28, 2026 found no recall of litter boxes, self-cleaning or otherwise. Check again before you buy a used self-cleaning box.

Frequently Asked Questions

How many litter boxes do I need for two cats?

Three. Cornell, the ASPCA and the AAFP all say one box per cat plus one, and the AAFP says to put them in at least two different places.

How big should a litter box be?

At least 1.5 times your cat's body length, per the AAFP. Measure from nose to the base of the tail; an 18 inch cat needs a box about 27 inches long.

Do cats prefer covered or uncovered litter boxes?

Most prefer uncovered, according to Cornell, because odor escapes and they can see around them. A covered box is fine for a cat that already uses one.

Can a kitten use a self-cleaning litter box?

Only switched off until it reaches the maker's minimum. PetSafe says to leave the ScoopFree unplugged until 6 months; Whisker says the Litter-Robot 4 cannot detect kittens under 3 lb in automatic mode.

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PetProofLab is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. We did not test these litter boxes; sizes and features are the makers' own, from their listings and manuals. This guide is for general information and is not veterinary advice.