Cat doors
Cat Doors Sized for the Cat You Actually Have
Cat doors are sized around a drill template. Here is how to size one around your cat, and the option renters never hear about.
Picks and specs last checked .
The complaint
“He squeezes through it sideways. It took a month to get him to use it at all, and now the neighbor’s cat comes in and eats his food.”
Cat doors are sold by the size of the hole you have to cut, not by the size of the cat. That’s backwards, and it’s why so many large cats end up squeezing through an opening that was designed around a drill template.
There’s also a version of this problem nobody sells a solution for: you rent, and you’re not cutting a hole in anything.
Why it fails
- The flap is sized to the tool, not the animal. A 6-inch flap fits the hole saw. It doesn’t fit a 9-inch-wide cat.
- The sill sits on the floor. Installation instructions put the door at the bottom of the panel because that’s where the template goes. Cats step through openings at chest height; a floor-level flap makes them duck and climb.
- The clever door has a battery. Microchip readers keep the neighbor’s cat out until the batteries die, and then the door does whatever its designers decided a dead door should do. Few listings say which.
- Renters get nothing. Every mainstream product assumes you own the door.
On weather
A single flap is a draft. In a wet or cold climate, look for a dual flap or a magnetic seal, and check whether the magnet is strong enough that your cat can still push through it. The two requirements pull against each other and manufacturers rarely say which way they’ve resolved it.
What to look for
Check every one before you buy. This is the part the pin couldn't fit.
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Measure your cat's shoulders, then add 2 inches
Shoulder width at the widest point is the number that matters. Most standard flaps run about 6 to 7 inches wide, which is fine for an average cat and too narrow for a Maine Coon or a large Ragdoll. Those often need 9 inches or more. A cat that has to compress to get through will start using the door less, then stop.
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The flap bottom should sit at the cat's belly, not on the floor
Cats step through a cat door. They don't crawl. If the opening starts at floor level they have to duck and climb, which is awkward enough that older or stiffer cats give up on it. Measure floor to the bottom of the chest and set the flap sill just below that.
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Check the battery before you buy the feature
Microchip and collar-tag doors solve a real problem, the neighborhood cat helping itself to your kitchen. They also die. Find out what battery it takes, what the claimed life is, and whether it fails open or locked when flat. A door that locks your cat out at 2 a.m. is a different product than the one you thought you bought.
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A four-way lock
In only, out only, both, neither. You will want "in only" the evening before a vet appointment, and you'll want it badly.
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If you rent, a window insert or a door panel, not a hole
Sash inserts and panels that replace a single pane give you a cat door with no cutting and no patching. They come out when you leave. This is the option almost nobody knows exists, and it's the difference between having a cat door and not.
The fixes
Products that pass, and where each one falls short
Every card below lists the product's known flaw. If we can't name one, we don't list it.
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Picks for this guide are still being tested. Check back soon.
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The measurement to take, the flap height most doors get wrong, and the renter option. We'll also email you when something in this category actually passes, which isn't often.