How to Choose a Cat Litter Box: Size, Hoods, and the Odour Problem

House-soiling is one of the most common behavioural complaints in cats, and the box itself is often the cause. Elimination behaviour comes down to three things: what the substrate feels like, whether the cat feels secure, and odour. Every one of those is a design variable, which means a litter box is a behavioural appliance rather than a container. In this guide we go through count, size and placement, the hooded versus open question, why odour is really a chemistry problem, and what automation does and does not change. Our picks are boxes we stock, with the trade-offs listed.

Count, Size, and Placement Come First

The long-standing guideline among feline behaviourists is one box per cat plus one, spread around the home rather than lined up in a single room, so no cat can guard access to all of them at once.

Length is the dimension that matters most. A cat should be able to turn completely and dig without meeting a wall, which in practice means a box around one and a half times its body length. Large breeds are routinely under-served by standard sizes, so measure rather than assume. Entry height matters at both ends of life: kittens and arthritic seniors need a low step in.

Are Covered Litter Boxes Better?

Hoods trade two benefits against each other. An enclosure contains scattered litter, screens the box visually, and gives a nervous cat privacy. It also concentrates odour inside the chamber your cat has to enter, and it removes the sightlines some cats depend on. In a multi-cat home, being cornered is a real risk rather than a theoretical one.

An enclosed box with a transparent cover is a sensible middle position: you keep the containment without losing the ability to see what is happening inside.

Odour Is a Chemistry Problem

Litter box odour is largely ammonia, released when bacterial urease breaks down urea in urine. Time is the governing variable: the longer waste sits, the more ammonia is produced, whatever the box is made of. Sealed enclosures, filters, and scented additives slow the escape of odour without changing how much is created.

Removal frequency is the real control. Which means the odour question and the cleaning question are the same question, and any box that is awkward to clean will smell.

What Automation Actually Changes

Self-cleaning boxes attack frequency directly by sifting after each visit, which keeps the substrate cleaner than most manual routines manage. App-connected units add something arguably worth more than the saved labour: they log how often your cat visits and how long each visit takes. Shifts in elimination frequency are early indicators of urinary tract disease, diabetes, and kidney disease, and they are easy to miss by eye.

Assess the safety system before the app. You want weight sensing, motion detection, and a cycle that halts and reverses on obstruction, plus a chamber that comes apart for washing without tools.

What to Avoid

• Scented litter. Formulated for human noses and a frequent trigger for avoidance. Given a free choice, most cats pick fine-grained, unscented clumping litter at a depth of two to three inches.
• Boxes that do not dismantle. If you cannot get into every corner, you are managing odour rather than removing it.
• High sides for a senior cat. Arthritis is common and under-diagnosed in older cats, and a high step is a silent reason for going next to the box instead of in it.
• Changing two things at once. When you change litter, box, or location, move one variable at a time. Set the new box beside the old one, keep both available for a fortnight, and let your cat decide.

How We Chose These Three

We kept boxes that are in stock, large enough for an adult cat to turn and dig, and that come apart for cleaning. Then we split them by household: one that hides the box as furniture, one built for odour control and easy washing, and one for a dog that needs an indoor or balcony option.

Deep Dive: Three Boxes We Stock

The Bottom Line

Six questions do most of the work. One box per cat plus one? Around 1.5 times body length, with room to turn and dig? An entry low enough for kittens and arthritic seniors? If it is enclosed, can your cat see out and leave freely? Does any automatic cycle have obstruction stop and weight sensing? And does the whole thing come apart for washing?

A box chosen on those terms gets used without negotiation, which is the only performance measure that counts. If your cat suddenly starts avoiding a box that used to be fine, treat it as a medical question first and call your vet.

FAQs

How many litter boxes do I need? One per cat, plus one, placed in different parts of the home. Two cats means three boxes, and grouping them in one room defeats the purpose because a single cat can then guard all of them.

How deep should the litter be? Two to three inches of fine-grained unscented clumping litter suits most cats. Deeper is not better, and scented litter is a common reason cats start going elsewhere.

Is an automatic box safe? Look for weight sensing, motion detection, and a cycle that stops and reverses on obstruction. Check that before you look at the app features, and confirm the chamber dismantles for washing.

My cat stopped using the box. What now? Call your vet first. Sudden avoidance is often a urinary tract problem, not a preference change. Once medical causes are ruled out, look at cleanliness, box size, entry height, and whether another pet can corner your cat at the box.