Covered vs open litter boxes: an honest comparison
Ask this question anywhere cat people gather and you will get two confident answers, both delivered as settled fact. Covered boxes are cruel little gas chambers, says one camp. Cats want privacy, says the other. What is striking is how much more certain both sides are than the actual evidence justifies — because there is evidence, there is not very much of it, and it does not say what either camp thinks it says.
I make litter, which means I hear about litter boxes constantly. Here is what is known, what is reasoning rather than data, and the setup variables I would fix before I would spend one minute arguing about a lid.
— Jing, Greater Toronto Area, Canada
The short answer
The one published study on the question found no overall preference when cats were offered both styles and both were scooped daily. A few individuals preferred each. So the honest position is: your cat has an opinion and the group does not — and the daily-cleaning condition is doing an enormous amount of work in that finding. Where covered boxes reliably lose is odor concentration, usable space, sightlines and your own scooping discipline. Where they reliably win is scatter control and keeping dogs out.
What the evidence actually shows
The study people cite — usually without having read it — is Grigg, Pick and Nibblett, published in the Journal of Feline Medicine and Surgery in 2013. Twenty-eight cats were given a choice between a covered box and an uncovered box in their own homes. Waste was scooped from both daily and the amounts were compared.
The result: no statistically significant difference in use between the two styles. Broken down by individual, four cats preferred the covered box, four preferred the uncovered box, and the remainder used both. The authors' conclusion was that if boxes are kept sufficiently clean — at minimum once-daily cleaning — most cats will not show a preference, and their recommendation was to offer an individual cat a cafeteria of box styles and see what it picks.
Three things follow from that, and it is worth being disciplined about them.
One: anyone telling you covered boxes are categorically wrong is going further than the data. Two: anyone telling you cats want privacy is also going further than the data. Three: the entire finding is conditional on daily scooping, which is precisely the habit a hood makes easier to skip. Twenty-eight cats is also a small sample in a single study, so treat this as the best available evidence rather than the last word.
Where each design genuinely wins
Below is the comparison stripped of tribal loyalty. Some of these rows are supported by the study above; most are mechanical reasoning about what a lid physically does, which I have flagged in the notes underneath.
| Covered box | Open box | |
|---|---|---|
| Measured preference | No group-level advantage; a minority of individuals prefer it | No group-level advantage; a minority of individuals prefer it |
| Odor for the cat | Concentrated in a small, poorly ventilated volume at nose height | Disperses into the room instead of pooling around the cat |
| Odor for you | Better — which is the actual reason most people buy one | More noticeable, which at least tells you when to scoop |
| Usable space | The hood shrinks the effective footprint and limits turning and squatting | Full floor area, no ceiling, any posture the cat wants |
| Sightlines | One exit, no view out — a real issue in multi-cat homes | The cat can see who is approaching and leave in any direction |
| Scatter and tracking | Genuinely better at containing an enthusiastic digger | More scatter, unless you use high sides or a mat |
| Dogs and toddlers | Meaningful deterrent | No barrier at all |
| Your scooping habit | Out of sight, out of mind — the biggest hidden cost | Visible, so it nags you into the habit the evidence depends on |
| Health monitoring | Harder to notice changes in urine volume, frequency or stool | You see the box every day, which is how early problems get caught |
Preference row reflects Grigg EK, Pick L, Nibblett B. Litter box preference in domestic cats: covered versus uncovered. Journal of Feline Medicine and Surgery 2013;15(4):280–284 — 28 cats, both boxes scooped daily, no significant group difference, 4 individuals preferring each style. The remaining rows are mechanical reasoning and common clinical advice rather than findings from that study; they are stated as such deliberately.
The odor problem nobody accounts for
A hood does not remove odor. It redirects it. The room smells better because the smell is being held somewhere else, and that somewhere else is a small unventilated box your cat has to put its head inside several times a day. Since a cat's sense of smell is considerably sharper than ours, not smelling it is not evidence that it is gone.
The instinct at this point is to fix the smell with a scented litter or a scoop of deodorizing beads, which puts a manufactured fragrance into the same small volume, on top of the ammonia. That is two irritants where there was one — I went through the mechanics of this in the piece on scented versus unscented litter. If you use a covered box, the levers that actually work are scooping more often and using a litter that clumps firmly enough that nothing soiled stays behind.
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Five things that matter more than the lid
Size — by a wide margin the biggest one
A common rule of thumb is a box at least one and a half times your cat's length from nose to tail base, so it can turn, dig, squat and cover without touching a wall. Most boxes sold in stores are smaller than that for an average adult. An under-bed storage tub or a plastic sweater box costs less than a designer hood and solves more. Box size is the single most commonly missed cause of cats peeing outside the box.
Number and distribution
The standard guidance is one box per cat plus one, and — the part everyone skips — spread across different rooms. Three boxes lined up against the same wall function as one large box from your cat's point of view. We went through the arithmetic in how many litter boxes multi-cat homes need.
Location
Quiet, but not a dead end. Cats like to be able to see what is coming and to have an exit route, which is why a corner with a view of the doorway beats a closet or a cabinet. Keep boxes away from washers, dryers and furnaces — an unexpected bang while a cat is mid-squat can sour it on that box permanently — and away from food and water bowls.
Depth and no liners
Enough litter that your cat can dig a proper hole and bury the result without scraping the plastic floor. Skip plastic box liners: claws catch on them, and the moment a cat feels plastic instead of substrate you have undermined the whole digging experience the box exists to provide.
Scooping frequency
At least once daily, more if you can. This is the condition the preference evidence is built on, and it is the variable most within your control. It is also why I am wary of hoods: they do not make boxes dirty, they make dirty boxes easy to ignore.
One related note, since it comes up whenever setup does: toilet training a cat is a bad trade even when it works. It removes the daily look at urine volume, frequency and stool consistency that catches urinary and digestive problems early, and it takes away the digging and covering sequence entirely. Litter box care is boring. Boring is the feature.
Run the cafeteria test on your own cat
The study's authors gave the most useful piece of advice in this entire debate, and it is free. Stop arguing about what cats prefer and find out what your cat prefers.
How to run it
- Set out both styles at once, a reasonable distance apart in different spots
- Make them equal on everything else — same litter, same depth, same size if you can
- Scoop both at least once a day, since an unequal cleaning schedule invalidates the test
- Give it a week or two, not two days
- Watch which one gets used, and how — digging and covering matter as much as volume
- Keep the winner, and change one variable at a time from there
Signs your cat has already voted
- Hovering on the rim or keeping paws on the edge
- Not covering, or covering with a token scrape
- Straight in and straight out with no digging
- Scratching the wall or the outside of the box instead
- Eliminating right beside the box
- Any new avoidance — call your vet first, since urinary problems present this way and are urgent in male cats
If your cat has already stopped using the box, work the problem systematically rather than by trial and error — our behavior-first checklist is the order I would go in, and the complete box care guide covers the maintenance side.
Straight talk
If I had to set up a box for a cat I had never met, I would use a large open box in a quiet corner with a view of the room, unscented litter, and a mat underneath for tracking. That is a preference built on the failure modes I hear about most, not a claim that the evidence proves hoods are harmful — it does not. If you have a covered box and a cat that uses it happily every day and you scoop it daily, you do not have a problem, and you should not go rearranging a working system because of a blog post. The scatter argument for hoods is also real; if that is what is keeping the box in an acceptable spot in your home, that is a legitimate trade. Just make it knowingly, and account for the scooping.
Do cats prefer covered or uncovered litter boxes?
On average, neither. In the one published study, 28 cats offered both styles with both scooped daily showed no significant group preference; four preferred each. The authors recommended offering an individual cat a cafeteria of styles. Note the condition: daily cleaning.
Are covered litter boxes bad for cats?
Not inherently, but they concentrate odor in the small space your cat breathes, shrink the usable area, remove sightlines that matter in multi-cat homes, and make it easier to forget to scoop — which is the habit the evidence for indifference depends on.
Do covered litter boxes smell worse?
Better to you, worse inside. A hood contains odor rather than removing it. The fix is scooping frequency and firm-clumping litter, not fragrance or deodorizing beads added into that same enclosed volume.
What size should a litter box be?
A common rule of thumb is at least one and a half times your cat's length from nose to tail base. Most retail boxes are smaller than that for an average adult cat. Storage tubs are a cheap way to get a genuinely large box.
Should I take the lid off my covered box?
If your cat is using it happily, leave it. If your cat hovers on the rim, will not cover, or goes beside the box, removing the lid is a free experiment — take the swinging door off first. Change one thing at a time, and see your vet before assuming new avoidance is about furniture.
Whatever box you use, the litter is doing the heavy lifting
Firm clumps mean nothing soiled stays behind — which matters most inside an enclosed box. Our 12 kg bulk bag, about 26 pounds of unscented cassava litter, is $64.99 with free shipping in the US as of August 2026.
By Jing Xue, founder of Noisy Lion, a Canadian brand developed in the Greater Toronto Area. Preference data cited from Grigg EK, Pick L, Nibblett B, Litter box preference in domestic cats: covered versus uncovered, Journal of Feline Medicine and Surgery 2013;15(4):280–284 — a single study of 28 cats. Other comparisons in this article are mechanical reasoning and common clinical guidance, not findings from that study. Nothing here is veterinary advice: new or sudden litter box avoidance warrants a veterinary exam, and straining or inability to urinate in a male cat is an emergency. Pricing and specifications reflect August 2026 and may change.
