Best Large Cat Litter Box: 6 Picks and the Size You Need
Most 'large' boxes are shorter than vets recommend for big cats. Here's how to check yours, and six boxes that fit.
The best large cat litter box is longer than most boxes sold as “large.” Vet guidelines call for a box about one and a half times your cat’s length, often 27 inches or more for a big cat. In our measurements, most boxes sold as large came in at 19 to 24 inches. Here’s how to size a box, plus six picks by length.
Heads up: this post contains affiliate links. If you buy through them, I may earn a commission at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Prices and stock change often, so always check the retailer’s page.
Here are the picks. Each name jumps to its full write-up, including who should skip it.
- IRIS USA XX-Large High Sided: longest box, best overall
- KittyGoHere Lucky Champ: best low-entry large box
- Tidy Cats Breeze XL System: best large pellet system
- Booda Dome Cleanstep: best large box for seniors
- Nature’s Miracle Hooded Corner: best corner box
- Van Ness Pureness Giant: best budget pan
If you have a genuinely big cat, start with the IRIS USA XX-Large. At 30 inches, it’s the longest box here and fits cats up to 20 inches long by the vet guideline. I haven’t tested it yet, so its specs come from the listing.
Our top pick
IRIS USA XX-Large High Sided
At 30 inches, long enough for a 20-inch cat by the vet guideline, with 14-inch walls, a curved 6.5-inch entry and an open top that most cats prefer.
- Length
- 30 in
- Width
- 20 in
- Walls
- 14 in
Figures: Amazon listing, Sep 2026
See why it winsRunner-up Tidy Cats Breeze XL System — a pellet system whose XL size suits larger cats.
How Big Should a Litter Box Be?
The AAFP and ISFM, the main feline veterinary bodies, recommend a litter box about one and a half times your cat’s length, measured from nose to base of the tail. They also cite a study in which adult cats preferred a box of 34 by 15 inches. The American Veterinary Society of Animal Behavior (AVSAB) sums up that research simply: cats prefer larger boxes.
Here’s what the rule means for different cats:
| Cat length, nose to tail base | Minimum box length |
|---|---|
| 14 in | 21 in |
| 16 in | 24 in |
| 18 in | 27 in |
| 20 in | 30 in |
A big cat quickly outgrows a standard box. An 18-inch cat needs a 27-inch box, which rules out most boxes labeled “large.” That’s why a lot of large-breed owners end up choosing from a short list of extra-long boxes.
Use the checker below with your own cat’s measurement to see which of the six picks are long enough.
Box size checker
Box lengths use the longest floor side from Our measurements and product listings, Sep 2026. Measure your cat standing, from the tip of the nose to where the tail begins.
The Nature’s Miracle corner box is left out of the checker because its triangular shape doesn’t have a simple length.
Large Litter Boxes Compared
The table lines up the six picks by size and entry. Four boxes were rated after hands-on use in our home. Sizes for the IRIS, the Breeze XL and the Van Ness come from their product listings.
| Box | Size (L × W × H) | Style | Entry | Our rating |
|---|---|---|---|---|
| IRIS USA XX-Large High Sided | 30 × 20 × 14 in | Open, high sides | 6.5 in, curved | Not tested |
| Tidy Cats Breeze XL | 27.5 × 18.5 × 13.7 in | Pellet sifting system | Not stated | 8.2 (standard size) |
| KittyGoHere Lucky Champ | 24 × 20 × 5 in | Open | 3 in | 8.4 |
| Booda Dome Cleanstep | 22.5 × 22.5 × 19 in | Covered dome | Ramp | 8.0 |
| Nature’s Miracle Hooded Corner | 23 × 26 × 20 in | Covered corner | Not stated | 8.8 |
| Van Ness Pureness Giant | 21.25 × 17.1 × 9.25 in | Open, high sides | Not stated | Not tested |
Length is what matters most for a big cat, and only the IRIS and the Breeze XL clear 27 inches. The shorter picks earn their place in other ways: the KittyGoHere’s 3-inch entry suits older cats, and the Nature’s Miracle fits into a corner.
The 6 Best Large Cat Litter Boxes
Each pick below lists what stands out, what to watch for, and who it suits. Four picks went through our hands-on test. I haven’t tested the IRIS and the Van Ness yet, so their details come from the product listings.
Longest box overall
IRIS USA XX-Large High Sided
Best forBig cats, including Maine Coons and Ragdolls, that need length and high walls.
Skip it ifFloor space is tight; it's 30 by 20 inches.
What stands out
- Longest box here at 30 inches
- 14-inch walls hold in scatter and spray
- Open top, which most cats prefer, per Cornell
Watch out for
- Not tested by us yet
- Large footprint
- 6.5-inch entry is higher than low-entry boxes
Length is the whole point of a large box, and the IRIS delivers 30 inches, enough for a cat up to about 20 inches long by the vet guideline. Its 14-inch walls and curved 6.5-inch entry keep litter and spray in, and the open top suits the many cats that dislike lids. I haven’t found a hands-on test, so these details come from the listing.
Best low-entry large box
KittyGoHere Lucky Champ
Best forSenior cats, cats with stiff joints and kittens.
Skip it ifYour cat kicks litter hard; the low walls won't stop it.
What stands out
- Very low 3-inch entry
- Plenty of room to dig
- Molded rim adds stability
Watch out for
- Low walls offer little scatter protection
- 24 inches long
- Pair it with a litter mat
A 3-inch entry makes this the easiest box here to step into. It’s spacious, with plenty of room to dig. The trade-off is low walls, so a litter mat underneath helps. My cat litter mat guide compares the options.
Best pellet system
Tidy Cats Breeze XL System
Best forOwners who like the pellet-and-pad system.
Skip it ifYou want to use regular clumping litter.
What stands out
- Over 27 inches long in its XL size
- Reusable pellets and absorbent pad
- XL size suits larger cats
Watch out for
- Needs Breeze pellets and pads, not regular litter
- Some users find the standard size too small
- Ongoing cost of pads
The Breeze is a system rather than a plain box: urine passes through reusable pellets onto a pad underneath. The standard size is too small for many cats, so get the XL, with taller sides, for larger cats. The XL kit’s listing gives 27.5 inches of length, enough for a cat up to about 18 inches long.
Best large box for seniors
Booda Dome Cleanstep
Best forOlder cats that want a covered box with an easy entry.
Skip it ifYour cat dislikes covered boxes or is very long.
What stands out
- Textured ramp is easy for seniors
- Spacious interior with plenty of headroom
- Carbon filter for odor
Watch out for
- Some owners report the lid doesn't lock securely
- 22.5 inches long
- Covered, which many cats don't prefer
The Booda Dome’s ramp makes it our pick for senior cats, and its round shape gives plenty of turning room. At 22.5 inches, it’s best for average-length cats rather than giants. Check that the lid seats firmly after cleaning.
Best corner box
Nature's Miracle Hooded Corner
Best forAverage to large cats in rooms where a corner is the only free spot.
Skip it ifYour cat is very large; corner boxes may feel cramped.
What stands out
- Our top-rated box at 8.8 out of 10
- Roomy for a corner box
- Non-stick coating and charcoal filter for odor
Watch out for
- Very large cats may find it cramped
- Triangular shape limits usable length
- Covered, which many cats don't prefer
I rated this 8.8: it’s generously sized for a space-saving design. The triangular shape tucks into a corner, and a non-stick base helps with odor. Very large cats may still find corner boxes cramped, so it suits average to large cats rather than giants.
Best budget pan
Van Ness Pureness Giant
Best forAn extra box for an average-size cat on a budget.
Skip it ifYour cat is long; at 21 inches it suits cats up to about 14 inches.
What stands out
- Higher sides than most budget pans
- Sold for large cats that like to dig
- Polished finish resists odor and stains, per the listing
Watch out for
- Not tested by us yet
- 21 inches suits cats up to about 14 inches long
- Basic design
This is a simple, cheap pan with higher sides than most at its price. The listing gives 21.25 inches of length, fine for an average cat and handy as the extra box the n+1 rule calls for. For a genuinely big cat, the IRIS or the Breeze XL makes a better main box.
Covered or Open for a Big Cat?
A lid limits headroom, which matters more for a big cat. Cornell notes that most cats prefer an uncovered box, and the AVSAB adds that covered boxes limit a cat’s view, which matters in multi-cat homes.
That said, research shows many cats have no strong preference either way. The practical answer is to start with an open box like the IRIS, and try a covered one such as the Booda Dome only if your cat seems to want more privacy. My guide on how many litter boxes per cat covers placement and multi-cat setups.
What About a DIY Storage Bin Box?
Many owners of very large cats make their own box from a big plastic storage bin, cutting an entry in one side. It’s a cheap way to get more length and higher walls than most commercial boxes. If you try it, sand the cut edge smooth, keep the entry low enough for your cat, and use clumping litter about two inches deep.
It isn’t a product I can recommend by test data, but it’s a common workaround when nothing on the shelf is long enough. My guide on how deep cat litter should be includes a calculator for how much litter a big box takes.
My Verdict on Large Litter Boxes
Bottom line
For a big cat, the IRIS USA XX-Large High Sided is the best large cat litter box. At 30 inches, it suits cats up to about 20 inches long by vet guidelines, the longest box here, and its open top suits most cats. For a pellet system, choose the Breeze XL, and for seniors, the low-entry KittyGoHere.
Measure your cat from nose to base of tail, multiply by one and a half, and buy a box at least that long. Prices change often, so check the retailer’s page before you buy.
Frequently Asked Questions
How big should a big cat’s box be?
About one and a half times your cat’s length from nose to base of the tail, according to AAFP and ISFM guidelines. An 18-inch cat needs a box around 27 inches long, and a 20-inch cat needs about 30 inches, longer than most boxes sold as large. The same guidelines cite a study where adult cats preferred a 34 by 15 inch box.
What is the biggest litter box you can buy?
The IRIS USA XX-Large High Sided box is the longest pick here, at 30 by 20 inches according to its listing. The Tidy Cats Breeze XL comes next at about 27.5 inches. For even larger cats, some owners convert a big plastic storage bin, which can be longer than most commercial boxes.
Do Maine Coons and Ragdolls need XL boxes?
Usually, yes. Both are large breeds, and a long cat needs a box about one and a half times its length. Measure your cat from nose to base of tail rather than going by breed, then choose a box at least that long. Many boxes labeled large fall short.
Are covered litter boxes okay for big cats?
They can be, if the box is tall and long enough. Cornell says most cats prefer uncovered boxes, and lids limit headroom for big cats. A box with a removable lid lets you try both. Research shows many cats don’t strongly prefer either.
Is a storage bin a good litter box?
It can be a practical option when commercial boxes aren’t long enough. Choose a bin at least one and a half times your cat’s length, cut a low entry, and smooth the cut edge so it can’t scratch. Keep litter about two inches deep and scoop daily.