What Do Pets Need
Your answer

What size litter box?

International Cat Care and the AAFP/ISFM guidelines, from the American Association of Feline Practitioners and the International Society of Feline Medicine, both size a litter box at one and a half times your cat’s length, nose to the base of the tail. International Cat Care warns that many standard-sized trays are too small.

Litter box length

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A cat walking, with a line from its nose to the base of its tail, beside a rectangular open litter box with a line along its length one and a half times as long.
Measure your cat from the nose to the base of the tail, leaving out the tail, and look for a box half as long again.

Shape, sides and lids

Both recommend a rectangular box. Humane World for Animals wants one large enough for the cat to turn around comfortably, and low enough to step in and out easily.

The AAFP/ISFM guidelines recommend open boxes whenever possible, as they make it easier to keep an eye on the box and scoop often, and they say small covered boxes may make it hard for larger cats to get into position. ASPCA says most cats don’t like lids or box liners, and International Cat Care says large breeds may find smaller hooded trays hard to use.

Boxes on sale

Makers give outside sizes, so the floor inside is shorter. Petmate’s Basic Hooded Cat Litter Pan is 24 x 19 x 18.5 in in Jumbo and 18.8 x 15.2 x 14 in in Large, and both sizes of Catit’s Airsift box are 22.4 in long. Even the Jumbo is short of the 27 in an 18 in cat needs.

For a bigger box, ASPCA suggests a plastic sweater storage container.

How many boxes, and how deep to fill them, is on how many litter boxes per cat.

Common questions

Is a corner litter box a good idea?

No, International Cat Care recommends rectangular trays, which give more room than corner, triangle or oval ones.

What size litter box does a kitten need?

International Cat Care says a kitten can start with a smaller tray, as long as it's replaced with a bigger one as the kitten grows.

Keep going

How many litter boxes per cat?What does a new kitten need?What size cat carrier?

Where we get our information from

Litter box sizing comes from International Cat Care, the AAFP and ISFM house-soiling guidelines, ASPCA and Humane World for Animals; box sizes from Petmate and Catit. Checked against published data from International Cat Care, AAFP and ISFM, ASPCA, Humane World for Animals and Petmate (plus 1 more).

See all 6 sources
  • International Cat Care, Choosing a litter tray for your cat
  • AAFP and ISFM Guidelines for diagnosing and solving house-soiling behavior in cats (J Feline Med Surg 2014;16(7):579–598), full text on PubMed Central
  • ASPCA, Litter Box Problems
  • Humane World for Animals, How to litter train a kitten or cat
  • Petmate, Basic Hooded Cat Litter Pan
  • Catit, Litter Box with Airsift filter system

General care guidance from animal welfare charities, vets and makers' published sizes. It isn't veterinary advice: if your pet seems unwell or has eaten something it shouldn't, call your vet.