How to Choose Litter Box for Indoor Cat? 5 Proven Rules

Nothing derails indoor cat ownership faster than picking the wrong litter box. Your cat starts avoiding it, finds a corner of your bedroom rug instead, and you spend the next month trying to figure out what went wrong. I learned this the hard way. I bought a covered box because it looked tidy on a shelf, and within a week my cat refused to go near it. Knowing how to choose a litter box for your indoor cat is one of the most practical decisions you’ll make, and the rules are simpler than the pet store aisle makes them look. This guide covers size, type, material, placement, how many boxes you actually need, litter depth, liners, senior-cat access, small-apartment setups, and the mistakes that drive even cooperative cats away.

Quick answer: choose a large open rectangular litter box that is at least one and a half times the length of your cat from nose to tail. Place it in a quiet low-traffic spot away from food and water. Use one box per cat plus one extra, in separate locations. Scoop daily and do a full litter change every one to two weeks with unscented clumping litter.

 

How to Choose a Litter Box for Your Indoor Cat in 7 Steps

If you only read one section, read this one. Each step links to the part of the guide that explains the reasoning.

1. Measure your cat. Nose to base of tail, then multiply by 1.5. That’s your minimum box length. See how to measure.
2. Pick an open box. Skip the hood unless your cat has shown she prefers one. See open vs. covered.
3. Match the type to your cat’s age and agility. Top-entry boxes suit young, nimble cats only. See box types.
4. Choose the material. Stainless steel lasts longest. A storage tote is the cheapest way to get a big box. See materials.
5. Buy one box per cat, plus one. Put them in different rooms. See placement.
6. Fill it with 2 to 3 inches of unscented clumping litter. Use 1 to 2 inches for seniors. See litter.
7. Watch what she does for a week. If she hesitates, perches on the edge or goes elsewhere, adjust size, litter or location before anything else. See troubleshooting.

 

Why Litter Box Size Is the Most Important Decision

The most common litter box mistake owners make is buying one that’s too small. Many boxes in the pet store aisle are sized for shelf appeal rather than for a cat who needs to turn around. A properly sized litter box should be at least one and a half times the length of your cat, measured from the tip of its nose to the base of its tail. Some behaviorists go further and say bigger is simply better, and if you have the floor space, they have a point.

Litter box size determines whether your cat can comfortably turn around, dig and cover its waste without feeling cramped. A cat that feels squeezed into a box will start eliminating outside it, not because of attitude but because the box has become physically uncomfortable to use. For an average adult cat that means a box at least 22 to 24 inches long, with walls at least 4 inches high.

Here is a simple size reference based on cat size:

Cat Size	Minimum Box Length
Kitten under 6 months	16 to 18 inches
Average adult cat	22 to 24 inches
Large breed (Maine Coon, Ragdoll)	26 to 30 inches
Senior cat with joint issues	22 to 24 inches with an entry under 3 inches

How to Measure Your Cat for a Litter Box

1. Let your cat stand relaxed on a flat surface. A treat on the floor helps her stay put.
2. Run a soft tape measure from the tip of her nose to the base of her tail. Skip the tail itself.
3. Multiply that number by 1.5. A 16-inch cat needs a 24-inch box.
4. Measure the inside floor of the box you’re considering. Product labels often list outside dimensions, and the rim and walls can eat two or three inches.

[IMAGE PLACEHOLDER: simple diagram showing where to measure a cat from nose to base of tail, with the 1.5x formula labeled | Suggested alt text: “how to measure a cat for the right litter box size” | Suggested filename: how-to-measure-cat-for-litter-box.webp]

If you can’t find a commercial box large enough, a large plastic storage tote with one side cut down to create a low entry point works better than most marketed litter boxes and costs far less. That goes double for large breeds, where the 26 to 30 inch range is hard to find on a store shelf.

Insight: The storage tote hack is genuinely the best litter box upgrade most cat owners have never tried. A 66-quart storage tote gives your cat more usable space than almost any dedicated cat product on the market. Cut one short end down to about three inches for easy entry and you have a solid litter box for under fifteen dollars.

 

Open vs. Covered: Which Litter Box Do Most Indoor Cats Prefer?

Most cats do better with open litter boxes, and the reasons come down to smell and sightlines. Covered boxes trap odors inside the enclosed space where the cat is trying to eliminate. They concentrate ammonia that bothers a cat far more than it bothers an owner, and they create a confined space where the cat can’t monitor its surroundings for threats while in a vulnerable position.

Covered boxes appeal to owners because they hide the contents and contain litter scatter. But every ventilation benefit the owner gains comes at a direct cost to the cat’s comfort. Odor that dissipates quickly in an open box concentrates inside a covered one. Your cat smells everything far more acutely than you do, and what smells mildly unpleasant to you can register as overwhelming to your cat in an enclosed space. Covered boxes also block a cat’s exit routes and let other pets loom over the entrance while your cat is mid-use, which some cats find stressful enough to avoid the box entirely.

The one exception is a cat that seeks privacy and still uses a covered box willingly, with no signs of stress or avoidance. Test this by offering both types side by side and watching which one gets used more. Your cat will tell you directly through its behavior which it prefers.

Feature	Open Box	Covered Box
Odor inside the box	Disperses	Concentrates
Escape routes	Several	One
Litter scatter	More, unless sides are high	Less
Owner’s view of waste	Visible	Hidden, so it’s easy to skip scooping
Best for	Most cats, seniors, multi-cat homes	The occasional cat who clearly prefers privacy

How to Switch a Cat From a Covered Box to an Open One

1. Leave the covered box where it is. Don’t move it or take it away on day one.
2. Remove the lid or door but keep the base in the same spot. Give her a few days.
3. Put a new open box next to it with the same litter.
4. Once she’s using the open box, shift it to the permanent location a foot or two at a time.
5. Retire the old base only after she’s used the new setup reliably for a couple of weeks.

 

The 4 Main Types of Litter Boxes and Which Fits Your Cat

The four main litter box types each serve a different cat or owner need. Knowing which one fits your specific situation saves you from the trial-and-error cycle that wastes money and frustrates both you and your cat.

The open high-sided litter box is the best starting choice for most cats. High sides contain litter scatter and urine from cats that pee standing up, while keeping the box fully ventilated and visually open so the cat never feels trapped. Look for a box with sides at least seven to eight inches tall and one lower entry side for easy access.

The top-entry litter box works well for young, agile cats in small apartments where litter scatter is a real problem. Entry through the top naturally keeps litter from getting kicked out and contains tracking to the grate surface. But it’s difficult for senior cats, arthritic cats, large breeds and any cat with mobility limitations. Never use a top-entry box as the only option for a cat over ten years old.

Self-cleaning automatic litter boxes cut down on daily scooping and give you better odor control through sealed waste compartments. They also track usage patterns through companion apps, which makes them useful for spotting health changes early. The honest limitation: some cats refuse to use them after the noise and movement of the cleaning cycle spooks them. Always keep at least one manual box available during the transition. According to the Ohio State University Indoor Pet Initiative, the most important factor in any litter box choice is whether the cat will willingly use it, not which type seems most convenient to the owner.

Corner boxes and furniture-style enclosures work in apartments where space and looks both matter. They still have to meet the same size and ventilation requirements as any other box. A beautiful furniture piece that’s too small or too enclosed fails the cat no matter how well it fits your decor.

Type	Best For	Skip It If
Open high-sided	Most cats, standing urinators, multi-cat homes	You can’t tolerate any visible litter or waste
Top-entry	Young, agile cats and heavy litter scatter	Your cat is a senior, large or stiff in the joints
Self-cleaning	Busy owners and health-tracking fans	Your cat is noise-sensitive or nervous
Corner or furniture-style	Tight spaces where looks matter	The interior is under the size minimum or poorly ventilated

 

Litter Box Material: Plastic vs. Stainless Steel vs. Storage Tote

Type gets most of the attention in litter box shopping, but material matters almost as much and it’s rarely covered anywhere. Here’s how the three most common options actually hold up.

Material	Pros	Cons
Standard plastic	Cheap, widely available, lightweight	Scratches over time and holds odor; needs replacing every 6 to 12 months
Stainless steel	Doesn’t absorb odor, easy to disinfect, lasts for years	Costs more upfront; some cats dislike the sound of digging on metal
Plastic storage tote	Cheapest per square inch of space, easy to size up	Requires cutting an entry yourself; still scratches like standard plastic over time

Plastic is where most litter box odor complaints actually start. Daily scooping leaves microscratches in the surface, and those scratches trap bacteria that no amount of washing fully removes. Stainless steel doesn’t have that problem, which is why it shows up so often in senior-cat and multi-cat setups where owners are trying to eliminate every possible reason a cat might avoid the box. If you go with plastic, whether a storage tote or a commercial box, plan to replace it on a schedule rather than waiting until it looks dirty. It can smell to your cat long before it looks bad to you.

 

Litter Box Placement Rules That Most Owners Get Wrong

Placement determines whether your cat uses the litter box even when you’ve chosen the right size and type. A correctly sized open box in the wrong location gets avoided just as reliably as the wrong box in any location. The placement rules are straightforward, and they matter every single day.

Place the litter box in a quiet, low-traffic spot where your cat won’t get startled mid-use. Cats are physiologically vulnerable during elimination, and their nervous system responds to sudden sounds or movement by tagging the litter box location as a threat. A box next to the washing machine, in a busy hallway or near the front door creates exactly this problem. The cat starts associating the box with stress and looks for alternatives.

Keep the litter box away from food and water bowls at all times. Cats instinctively avoid eating near their elimination area, a pattern rooted in the need to avoid contaminating food sources. A cat with its feeding station and litter box crammed into the same corner will often cut back on using one or both.

 

How Many Litter Boxes Do You Actually Need?

The rule is one litter box per cat, plus one extra, and it applies to placement too. Two boxes placed side by side in the same corner count as one box in a cat’s territorial perception, not two. Spread them across genuinely different rooms.

Number of Cats	Minimum Boxes Needed	Suggested Placement
1 cat	2 boxes	One bathroom, one bedroom or hallway
2 cats	3 boxes	Spread across at least two separate rooms
3 cats	4 boxes	One per floor if you have stairs, plus a spare

For multiple cats, spread boxes across different rooms entirely so no single cat can guard or monitor every box from one spot. Some cats also prefer to pee in one box and defecate in another, which is a second reason the extra box matters even for a household with just one cat.

For more detail on the full litter box setup including depth of litter and cleaning schedules, check out our complete guide to indoor cat litter box setup and maintenance.

 

Setting Up a Litter Box in a Small Apartment

Small spaces make the “one box plus one extra, in different rooms” rule feel impossible. It’s not, but the choices get tighter. A studio can still work if you’re picky about where each box lands and how big it is.

Spot	Verdict	Why
Bathroom corner	Good	Quiet and easy to clean. Prop the door open so she can’t get shut out or shut in.
Bedroom corner	Good as the second box	Low traffic, and it gives her a second location. Smell is the trade-off, so scoop faithfully.
End of a hallway	Fine	Works if people don’t walk past it all day.
Kitchen or next to food	Avoid	She won’t want to eliminate where she eats.
Next to the washer, dryer or dishwasher	Avoid	A sudden spin cycle can scare her away from the box for good.
Inside a closed cabinet or small cupboard	Avoid	It’s a covered box with extra steps, and the smell builds up.

• Put the box where she can see the room’s entrance while she’s using it. Corners with a wall behind her and a view out are ideal.
• Go big on the box and small on the furniture. A 24-inch box beats a cute 18-inch one every time.
• If floor space is tight, use a tote under a console table or a low shelf with plenty of headroom, as long as she can see out on at least two sides.
• Use a textured mat just outside the entry to catch tracked litter, and keep a small hand broom and dustpan nearby.

[IMAGE PLACEHOLDER: small apartment floor plan or photo showing two litter box locations in different rooms, with food and water stations marked elsewhere | Suggested alt text: “litter box placement in a small apartment with two boxes in separate rooms” | Suggested filename: small-apartment-litter-box-placement.webp]

 

What Litter to Use and How Deep to Fill the Box

The best litter for most indoor cats is unscented, fine-grained clumping clay litter filled to a depth of two to three inches. Brand loyalty has little to do with it. Preference studies, where cats choose among options, keep landing on the same answer. Cats descend from desert-dwelling animals, and their instinct is to dig in fine sandy substrate. Fine-grained, unscented clumping clay matches that instinct more closely than any other type.

Scented litters are formulated to manage odor for the owner’s comfort, and that creates the opposite problem for the cat. A cat’s scent receptors are far more powerful than a human’s, so an artificial fragrance that smells pleasant to you registers as an overwhelming chemical intrusion in the enclosed space of a litter box. Many litter avoidance cases resolve completely once the owner switches from scented to unscented litter.

Two to three inches of litter gives most cats enough depth to dig and cover without wasting litter through excessive displacement. Less than two inches means the cat hits the box bottom while digging, which many cats find unpleasant. More than four inches causes cats to sink and shift on a loose, unstable surface, especially older or heavier cats. Long-haired cats sometimes prefer even less litter, or a smoother surface that doesn’t cling to their fur. If odor is a concern between full changes, a thin layer of baking soda under the litter helps absorb smell without the chemical intrusion of a scented product.

Insight: If your cat has been avoiding the litter box and you haven’t changed anything obvious recently, check the litter first. Switching brands often means switching formulas, particle sizes or scents even within the same category. Cats notice these changes immediately and vote with their paws by going elsewhere. When trying a new litter, run it alongside the old one in a separate box for at least a week before fully switching.

Litter Box Cleaning Schedule

How Often	What to Do
Every day	Scoop clumps and waste. Top up litter to the 2 to 3 inch line.
Every 1 to 2 weeks	Dump all the litter, wash the box with mild unscented soap and warm water, dry it fully, then refill.
Every 6 to 12 months	Replace plastic boxes. Stainless steel stays on the shelf until it’s damaged.

Skip strong-smelling cleaners and anything with ammonia. Ammonia smells a lot like urine to a cat, and a box that smells of urine invites her to go there again, or to avoid the spot completely.

 

Litter Box Liners: Worth It or Not?

Liners look like an obvious upgrade. Line the box, pull the drawstring, toss the bag, done. In practice, many cat behaviorists advise against them, and it’s worth knowing why before you buy a box of fifteen.

Cats dig and scratch to bury waste, and claws puncture liners. Once a liner has holes, urine pools underneath it instead of getting absorbed by the litter, which creates a worse odor problem than not using one at all. Liners that don’t fit the box perfectly bunch up in the corners, and some cats get a claw caught in the folds while covering waste. A single bad experience like that can be enough for a cat to start avoiding the box altogether.

If you want to try one anyway, look for a liner sized specifically for your box rather than a generic one, and watch your cat’s behavior for the first week. If you notice more digging near the edges, holes appearing, or any hesitation stepping in, drop the liner and go back to a clean, unlined box scooped daily. That single habit does more for odor control than any liner will.

 

Litter Box Height and Access for Senior or Arthritic Cats

A litter box that worked fine for your cat at age three can become a real obstacle at age thirteen. Standard boxes have walls five to seven inches tall, and that height turns into a painful step for a cat with arthritis or joint pain. This is one of the most overlooked causes of “sudden” litter box avoidance in older cats, and owners frequently mistake it for a behavior problem when it’s actually pain.

For a senior or arthritic cat, look for an entry height of two to three inches, so your cat can walk in rather than step or jump over a lip. The box itself should still be spacious, roughly 1.5 times body length as with any adult cat, since a cramped interior forces the kind of turning and pivoting that hurts stiff joints. Keep litter depth on the shallow side, around one to two inches, since a deep, shifting surface is harder for a wobbly senior cat to stand on.

A few practical fixes:

• Cut a low entry into one side of a plastic storage tote, the same hack recommended earlier for size, using a jigsaw or utility knife on a clean, dry box.
• Add a second box on each floor of the house if your cat has to climb stairs to reach the current one.
• Choose a stainless steel or well-cleaned plastic surface with good traction, since slippery bottoms make cats hesitant to enter.
• Skip the top-entry box entirely once a cat shows any sign of joint stiffness. It’s the hardest design for an aging cat to use.

If your senior cat starts urinating right at the edge of the box or just outside it, treat that as an access problem first, not defiance. Lower the entry before assuming it’s behavioral, and mention the change to your vet at the next visit since joint pain in cats is easy to miss without a hands-on exam.

 

The Litter Box Mistakes That Cause Most Avoidance Problems

The most damaging mistake is choosing a box that’s too small and never realizing it. Most commercial cat litter boxes marketed for adult cats are too short for an average adult cat to use comfortably. Owners buy them because they’re labeled for adult cats and never connect the undersized box to the elimination problems that build up over months.

The second mistake is cleaning the box too rarely. Cats need a clean litter box the same way you need a clean toilet. A box that isn’t scooped daily builds up odor and texture changes that make it progressively less acceptable. Many cats that seem to have a litter avoidance problem are really reacting to a box that hasn’t been cleaned enough. Scoop every day without exception and do a full litter change every one to two weeks.

The third mistake is replacing the litter box too rarely. Plastic litter boxes develop microscratches from regular use and daily scooping, and those scratches trap odor-causing bacteria that no amount of cleaning fully removes. The box itself starts to smell to your cat even when it looks clean to you. Replace plastic litter boxes every six to twelve months regardless of how clean they look, or switch to stainless steel and skip the replacement cycle altogether.

A fourth, smaller mistake worth naming: tracking mats get sold as an odor fix, but they only reduce scattered litter around the box, not smell. If tracking is your actual complaint, a textured mat right outside the entry catches most of it. If odor is your complaint, the fix is depth, cleaning frequency and unscented litter, covered above, not a mat.

 

Your Cat Won’t Use the New Litter Box? What to Try

Even a well-chosen box can get a cold reception at first. Change one thing at a time so you know what worked, and keep the old box available until she’s using the new one reliably.

What You See	Likely Cause	What to Try
Sniffs the new box and walks away	New litter, new smell or new spot	Put the new box beside the old one with the same litter. Move it later.
Perches on the rim or hovers	Box too small, or litter feels wrong	Go up a size. Switch to unscented, fine-grained clumping clay.
Pees just outside the edge	Entry too high, or sides too low for her posture	Lower the entry for seniors, or raise the sides for a standing urinator.
Pees in the box but poops elsewhere (or the reverse)	She wants a second location	Add another box in a different room.
Avoids the hooded box	Trapped odor or one exit	Take the lid off and see.
Scatters litter everywhere	Sides too low, or litter too deep	Use a high-sided box and a textured mat. Keep depth at 2 to 3 inches.

[IMAGE PLACEHOLDER: cat sitting at the edge of a new litter box while an older box sits beside it | Suggested alt text: “cat hesitating at a new litter box with the old box placed next to it” | Suggested filename: cat-wont-use-new-litter-box-transition.webp]

 

When Litter Box Avoidance Means a Vet Visit

Litter box avoidance that shows up suddenly in a cat with a previously reliable history is a medical signal until proven otherwise. Cats that start eliminating outside the box, or visit the box frequently with little or no output, may have a urinary tract infection, kidney disease, bladder crystals or diabetes rather than a behavioral problem. Check the behavioral possibilities first: box cleanliness, size and placement. But book a vet appointment within the same week if the avoidance is sudden or recent.

Watch specifically for a cat that makes multiple trips to the litter box within an hour and produces little or nothing each time. In male cats this pattern can signal a urinary obstruction, which becomes fatal without same-day emergency treatment. Don’t wait or monitor this pattern at home.

A cat that cries while in the litter box, has blood in its urine or repeatedly squats outside the box immediately after leaving it is showing signs of pain during elimination that need veterinary assessment regardless of how the litter box is set up.

This article is for informational purposes only. Always consult your vet if you have concerns about your cat’s health.

 

Quick Litter Box Checklist

• Box is at least 1.5x your cat’s nose-to-tail length, measured on the inside floor
• Open top, no hood or lid
• One box per cat plus one extra, in separate rooms
• Placed away from food, water and loud appliances
• Two to three inches of unscented clumping clay litter (one to two inches for senior cats)
• Scooped daily, fully changed every one to two weeks
• Plastic box replaced every six to twelve months, or upgraded to stainless steel
• Low entry (2 to 3 inches) for senior or arthritic cats

 

Frequently Asked Questions About Choosing a Litter Box

What size litter box does an indoor cat need?

The box should be at least one and a half times the length of your cat from nose to tail base. For an average adult cat that means a box at least 22 to 24 inches long. Most commercial boxes are too small. A large storage tote with one low-entry side cut down works better than most marketed options.

How do I measure my cat for a litter box?

Measure from the tip of her nose to the base of her tail while she stands relaxed, then multiply by 1.5. Compare that number with the inside floor length of the box, not the outside dimensions on the label.

Is a covered or open litter box better for cats?

Open boxes are better for most cats. Covered boxes trap odors inside the enclosed space, making the experience unpleasant for cats whose sense of smell far exceeds ours. Some cats tolerate covered boxes, but most prefer the ventilation, visibility and exit options an open box provides.

How many litter boxes does a single indoor cat need?

One cat needs two litter boxes at minimum. The rule is one per cat plus one extra, placed in genuinely different locations. Two boxes side by side in the same spot count as one box in a cat’s perception. Separate placement prevents the scenario where one dirty box leaves the cat with no acceptable option.

Where should I put a litter box in a small apartment?

Pick quiet corners such as a bathroom or bedroom, with the door propped open and a clear view of the entrance. Keep it away from food, water and appliances that start up suddenly. Avoid closed cabinets, which behave like a covered box.

Is it okay to keep a litter box in the bathroom?

Yes, as long as she can always reach it. Prop the door open or fit a cat flap so she can’t get locked out or shut in. Bathrooms are quiet and easy to clean, which makes them a popular choice.

What is the best litter to use in an indoor cat’s litter box?

Unscented, fine-grained clumping clay litter filled two to three inches deep is the best choice for most cats. Scented litters bother cats more than owners realize, because cats have a far more powerful sense of smell. If your cat has a respiratory condition, ask your vet about a low-dust litter formula before switching.

How often should I clean the litter box?

Scoop at least once daily without exception. Do a full litter change every one to two weeks. Wash the box with mild soap and water at each full change. Replace plastic boxes every six to twelve months, since scratches in the plastic trap bacteria that no cleaning fully removes.

Are litter box liners a good idea?

Usually not. Claws puncture liners, urine pools under the tears, and bunched-up liners can catch a cat’s paw while it’s covering waste. A clean, unlined box scooped daily controls odor better than a liner does. If you try one, use a snug, box-specific fit and watch for hesitation or holes in the first week.

Are self-cleaning litter boxes worth it?

They can be, for a calm cat and an owner who wants less daily scooping. The risk is a cat spooked by the motor. Keep a manual box available until she’s using the automatic one without hesitation, and check the waste yourself now and then so you notice health changes early.

How do I get my cat to use a new litter box?

Place the new box next to the old one with the same litter, and leave both out. Once she’s using the new one, move it a foot or two a day if you need it elsewhere. Don’t remove the old box until she’s used the new one reliably for a couple of weeks.

What litter box is best for a senior or arthritic cat?

A large, open box with an entry height of two to three inches, so the cat can walk in instead of stepping over a high lip. Keep litter shallow, around one to two inches, since a deep surface is harder to balance on. A sudden change in bathroom habits in an older cat often means the box is physically hard to use, not that the cat is misbehaving.

What is the best litter box for a large cat like a Maine Coon?

One that’s 26 to 30 inches long, open and with sides tall enough to hold litter in. Most store-bought boxes fall short, so a 66-quart storage tote with a cut-down entry is the usual workaround.

When should I switch a kitten to an adult-sized litter box?

Around six months old, or once the kitten box starts looking cramped, whichever comes first. Kittens under six months do fine with a smaller box, 16 to 18 inches long with low sides for easy entry, but they outgrow it fast during their first year.

Why is my cat peeing outside the litter box?

Check the box first: size, cleanliness, litter type and location. If the change is sudden, or she strains, cries or makes repeated trips with little output, call your vet within the week, or the same day for a male cat. Medical problems cause many sudden accidents.

 

Conclusion

Choosing the right litter box for your indoor cat comes down to a handful of decisions made correctly: the right size, an open design, a material that won’t hold odor, enough boxes in the right spots, and a setup that still works as your cat ages. Start today by measuring your cat and checking whether your current box meets the one-and-a-half-times rule. If it doesn’t, a storage tote upgrade costs about fifteen dollars and often resolves litter avoidance within days. For the complete setup guide covering litter depth, cleaning schedules and multi-cat arrangements, check out our detailed resource on indoor cat litter box setup.

To choose a litter box for an indoor cat, select an open rectangular box at least one and a half times the cat’s length from nose to tail, typically 22 to 24 inches for an average adult. Use one box per cat plus one extra, placed in separate quiet locations away from food and water. Fill with unscented, fine-grained clumping clay litter to a depth of two to three inches. Scoop daily, do a full litter change every one to two weeks, and replace plastic boxes every six to twelve months. Most cats prefer open boxes over covered ones for the better ventilation and visibility, and senior cats need a low entry of two to three inches to use the box without pain.