My partner is set on getting a kitten. We live in a terraced house, and I've heard horror stories of cats getting trapped in walls, behind large appliances, etc. by finding their way into places they've no business being.

Is there any guidance as to what is the minimum "safe" width of any gap, so as to prevent such accidents. I've already identified two places in our house that I'm going to have to cover, but there's smaller gaps (between a freezer and fridge, for example) that I'm wondering if I need to find solutions for.

I've found comments like the following on other Q&A sites:

They can fit through a hole that is a big as their head, nothing smaller.

If this is the case, then can someone give a rough indication of how large I can expect an average kitten (10-12 weeks old) head to be?

  • Even small gaps... youtube.com/watch?v=12wmyg9dfY8. Ours used to squeeze through the gap between the toilet waste pipe and the edge of the hole, and make their way under the bath (yay Victorian houses), to then squeak until I removed the bath panel for them. Tinkers.
    – Phil H
    Jul 25, 2014 at 12:47
  • 1
    On the other hand, cats generally magically acquire the ability to retrace their steps at dinner time, so it may just be enough to know where they have gone rather than prevent them going there.
    – Phil H
    Jul 25, 2014 at 12:51

3 Answers 3


For kittens that young, any gap or opening the size of a tennis ball or slightly smaller...should probably be blocked. (Approximately 2.5 inches.) That's at the smaller end. I would not leave gaps larger than 3 inches, unless you are prepared for the cat to get into those places.

Keep in mind: cats are contortionists, kittens doubly so. Even blocking all gaps wider than two inches MAY still leave an opening for a fuzzy adventurer to get into.

EDIT: it's been a few weeks since I answered this question, and a few days ago I adopted two 14-week-old kittens. And...yep, 2 inches wide is about the largest opening they can get into easily. Their teeny little skulls are about the size of a golfball.

  • thank you for such a prompt response, I'll get a tennis ball for testing. :)
    – user2716
    Jul 24, 2014 at 19:40

A good way of doing it would be having a room set up where there aren't any places the kitten could get stuck. Say, the bedroom with the bottoms of dressers blocked off.

That way, as you introduce your new kitten, you'll be able to accurately judge what places you need to cover, because you know the exact size of your kitten's head. You'll also be able to gauge what kind of trouble the kitten is likely to get into.

Some kittens don't like tight spaces, but some kittens also like climbing into high places. It's really just a matter of what your kitten happens to like, and you won't know until you spend some time with it.

The benefit of keeping the kitten in a single room while you work on kitten-proofing the rest of the house, is that it lets your kitten get used to all the new sounds and smells, and not become overwhelmed with all the new sights.


Able to answer this from experience. A 13 week old kitten can get through a gap/width of 1.5 inches (4 cms) and she's quite a big kitten. She also proceeded to then go behind kitchen unit and climb up the back of it, not just be underneath!

Quite a lesson I can tell you!

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