Most litter box complaints trace back to arithmetic, not attitude. A pan should measure at least 1.5 times your cat's body length from nose to base of tail, and most cats want 5–7 cm of litter depth — not the thin dusting a 4 kg jug spreads across a jumbo pan. Get those two numbers right before you buy anything else, then match the cat litter to the box style you've chosen.
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Shop Cat Litter →This guide walks through pan dimensions by measured cat length, litter depth in centimetres, how many boxes a one-cat or three-cat household actually needs, and which box-and-litter pairings hold up for sprayers, kittens and arthritic seniors. If you'd rather start with the litter itself, browse our cat supplies collection first.
Our top picks at a glance
These four picks cover the situations we're asked about most: a standard adult cat, a vertical sprayer, a multi-cat household fighting odour, and a dusty-covered-box problem.
- Petmate large open pan — the default for an average 45–50 cm adult cat who doesn't spray; low entry, easy to scoop, easy to scrub.
- Petmate high-sided / hooded box — for sprayers, kickers and cats who pee standing up; walls of 25 cm or more contain the arc.
- OdourLock clumping litter — for two or more cats, where odour at day 5–7 matters more than anything else.
- World's Best Cat Litter — plant-based, lightweight clumping litter that suits deep fills in big pans without a 15 kg lift.
- Naturally Fresh walnut litter — low-dust option when your cat uses a covered box and dust has nowhere to go.
How to choose
Five measurements decide whether a box works: interior length, wall height, entry height, litter depth and the number of boxes per household. Each one has a number attached.
1. Interior length = 1.5× your cat's body length
Measure from the tip of the nose to the base of the tail while your cat is standing. A 45 cm cat needs roughly 68 cm of interior length; a 50 cm Maine Coon-type cat needs about 75 cm. Commercial pans labelled "large" usually land between 48 and 60 cm, which is why so many big cats end up hanging over the edge. Width should be at least equal to body length — around 38–45 cm for most adults.
2. Wall height: 15 cm standard, 25 cm+ for sprayers
A 15–18 cm wall is plenty for a cat who squats and buries politely. Cats who urinate against a vertical surface or dig like they're excavating need 25–30 cm on at least three sides. That's the single most useful spec on a high sided litter box for sprayers.
3. Entry height: 12–15 cm for seniors and kittens
One low entry point keeps the box usable for a 10-week-old kitten or a 14-year-old cat with stiff hips. The American Veterinary Medical Association notes that mobility changes in senior pets often show up as litter box avoidance before they show up as limping — if a previously reliable cat starts missing the box, book a veterinary exam rather than assuming it's behavioural.
4. Litter depth: 5–7 cm, measured not guessed
Clumping clay and plant-based clumping litters both need 5–7 cm so urine forms a clump that lifts cleanly off the pan floor. Under 4 cm and clumps cement to the bottom. Over 10 cm and many cats simply refuse — our team at Ashario Pets hears "she started going beside the box after I switched to a deeper fill" more often than people expect. Non-clumping crystal products are the exception and usually sit at 2.5–4 cm per the label.
5. Box count: one per cat, plus one
The ASPCA recommends the n+1 rule: two boxes for one cat, three for two cats, four for three cats. Spread them across different rooms and at least one per floor in a two-storey home. Two boxes side by side read as one box to a cat.
Pick 1: Petmate large open pan — the baseline for an average adult cat
An open rectangular pan is the right starting point for roughly three-quarters of single-cat homes. Nothing blocks the sightlines, scooping takes under a minute, and there's no hood to trap ammonia.
What stands out is the practical stuff: smooth moulded corners that don't hold waste in a seam, a rim that accepts a liner if you use one, and a shape that fits a standard scoop without wedging. Fill it to 5–7 cm and expect to use roughly 5–7 kg of clumping litter for a full change in a large pan. Scoop twice daily, top up to depth weekly, and do a full dump-and-wash every 2–4 weeks with unscented soap and hot water.
Who should buy it: owners of cats under about 48 cm body length who bury normally, kittens graduating from a shallow starter tray, and anyone setting up the second box the n+1 rule requires. Pair it with a mat and see our cat grooming supplies if long-haired litter tracking is part of the problem.
Pick 2: High-sided and hooded boxes — covered vs open litter box, decided
High walls solve spray and over-the-edge urination; a hood solves visual mess and scatter. They're not the same fix, and the wrong one creates new problems. Here's how the two compare.
| Feature | Open high-sided pan | Covered hooded box |
|---|---|---|
| Best for | Sprayers, diggers, cats who stand to urinate | Scatter control, tidy corners, shy cats in busy rooms |
| Typical wall height | 25–30 cm on three sides, lower entry cut-out | Full enclosure, 20–25 cm interior clearance |
| Odour behaviour | Disperses; owner notices smell sooner | Concentrates inside; needs stronger odour-control litter |
| Dust exposure | Low | Higher — pair with low-dust litter |
| Multi-cat risk | Low — cat can see approaching housemates | Higher — single exit can be guarded |
| Price tier | $$ | $$$ |
| Shop at Ashario | Shop open pans and cat supplies | Shop litter for covered boxes |
In a multi-cat home, a hood plus a single doorway is a classic ambush point. The dynamics behind that are covered in detail in our guide to litter box problems in multi-cat homes. If you own one covered box and one confident cat plus one timid one, add an open pan elsewhere before you change litter.
Pick 3: OdourLock — for households at two cats and up
Odour control is a volume problem. Two cats produce roughly double the urine, and a box that smelled fine at day 3 with one cat can be noticeable by day 5 with two.
OdourLock is a Canadian-made tight-clumping clay litter built around sealing the clump rather than masking the smell with fragrance. At a 6 cm fill in a large pan, clumps lift intact, which is the real test — a clump that crumbles leaves residue behind and residue is what you smell on day 7. Customers often ask whether they can stretch a litter change by adding scented products on top; we'd rather they scoop twice a day and keep depth consistent.
Who should buy it: two- and three-cat households, apartments where the box shares air with the living space, and anyone using a covered box where odour has nowhere to go. Browse our full cat litter range and compare clump strength before committing to a 12 kg bag.
Pick 4: World's Best and Naturally Fresh — plant-based fills for deep pans and covered boxes
Plant-based clumping litters weigh substantially less than clay per litre, which matters when a jumbo pan needs 6 cm of depth across 60 cm of length.
World's Best Cat Litter uses whole-kernel corn and clumps firmly enough to scoop at a full 7 cm depth; it's the one we point to for owners carrying bags up to a third-floor walk-up. Naturally Fresh is walnut-shell based and runs low on airborne dust, which is the better match for hooded boxes where a cat's face sits inside the enclosure for a minute at a time. Neither is flushable in Toronto's system — bag and bin it.
Who should buy them: owners prioritizing lighter lifting, cats or people sensitive to dust, and anyone who's tried three clay litters and still has a tracking trail down the hallway.
The most common sizing mistake we see — and how to avoid it
The mistake is buying the box before measuring the cat, then blaming the litter. When a customer comes in describing a cat who urinates just outside the pan, our first question is interior length, and about half the time the pan is 15–20 cm shorter than the 1.5× rule requires.
Fix it in order. Measure the cat. Compare to the pan's interior length, not its exterior box dimensions. Check litter depth with a ruler, not by eye. Count boxes against n+1. Only then change litter brands. Pet owners tell us they've swapped litter three times before realizing a 42 cm pan was the actual problem for a 48 cm cat.
One related note on diet: hydration affects urine volume and concentration, and cats fed exclusively dry kibble typically drink less overall. The guaranteed analysis on canned food usually lists 75–82% moisture against roughly 8–10% in dry, and canned diets generally run fewer kcal per gram. Choosing a complete, life-stage-appropriate formula that meets AAFCO nutrient profiles — a point reinforced in AAFCO's 2026 model regulation updates — is the baseline; our wet cat food selection is a reasonable place to add moisture. Straining, frequent small urinations or blood are veterinary emergencies, not litter problems — see a vet the same day.
At a glance: Buy a pan at least 1.5× your cat's nose-to-tail-base length, keep clumping litter at 5–7 cm deep, and run one box per cat plus one spare across separate rooms. High sides (25 cm+) solve spraying; hoods solve scatter but concentrate odour and need a low-dust, tight-clumping litter.
Visit us at 1111A Finch Ave W, Unit 2, North York, ON M3J 2P7 — we're open 7 AM to 11 PM daily, and delivery is available across the GTA through apps like Uber Eats.
Shop the Brands Mentioned in This Article
Find OdourLock, World's Best Cat Litter, Naturally Fresh and Petmate pans in-store or Browse cat litter online →.
Common questions about litter box size and depth
What size litter box do I need for my cat's length?
Measure your cat from nose tip to the base of the tail, then multiply by 1.5 to get minimum interior length. A 45 cm cat needs about 68 cm; a 50 cm cat needs about 75 cm. Width should at least match body length. Large retail pans run 48–60 cm, so big breeds often need an oversized pan or storage tote.
How deep should cat litter be?
Fill clumping litter to 5–7 cm — deep enough for urine to form a liftable clump, shallow enough that most cats still dig willingly. Below 4 cm, clumps stick to the pan floor. Above 10 cm, some cats stop using the box entirely. Non-clumping crystal litters typically sit at 2.5–4 cm.
How many litter boxes per cat does a household need?
Use the n+1 rule: one box per cat plus one extra. One cat needs two boxes, two cats need three, three cats need four. Place them in separate rooms and at least one per floor. Boxes lined up together function as a single resource and don't reduce competition.
Is a covered or open litter box better?
Open pans suit most cats — better airflow, no trapped ammonia, and no single exit a housemate can block. Covered boxes are worth it mainly for scatter control or privacy in a busy room, and they require a low-dust, tight-clumping litter plus more frequent scooping. If your cat sprays, prioritize 25 cm+ walls over a hood.
Still unsure which pairing fits your household? Our team can walk you through pan dimensions and litter options in person — see cat wellness essentials, read our customer reviews, or contact our store team. More litter and behaviour guides live on our cat blog.
