Interested in a DIY cat door? I’m sharing how to install a cat door on an interior door without buying a cat door kit!

When we first moved in, we struggled with where to put the litter box. The house had lots of carpet and because it’s a split-level house, I felt like the litter box was a bit hard to hide (and keep clean). Ultimately, I decided that putting the litter box in the basement bathroom would work out great. That meant, however, that we needed to have a cat door to the basement because we had an interior door on our basement stairs.

So many things needed to be addressed when we moved in and the budget was really tight for all the things. So, I got crafty and decided to see if I could make my own DIY cat door. It worked and was so simple, so I’m sharing that with you today!

I do want to say that I did this project in 2012 and, since then, we’ve drastically changed our space. If I was doing this project now, I would paint the cat door frame that I put on to match the door. It would be an easy fix and one that would make it more seamless, but it’s something I just didn’t consider or think about in 2012.

Interior Door with Cat Door

Before we jump right in to the how-to, let me show you what our door looked like before we started the cat door installation project.

The interior door was hollow in the raised panel where we installed the DIY cat door. This project would work the same if you had a solid core door. Ok, let’s get to the tutorial!

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Supplies Needed to Install Interior Cat Doors

• Screwdriver
• Paint
• Paint Brush
• Deglosser
• Paintable Wood filler
• Square picture frames*
• Sawhorses
• Drill and drill bit
• Jig saw
• Air compressor
• Nail Gun
• Nails
• Sanding Pad

*When I did this project, I didn’t know how easy it was to cut and install trim so I used square picture frames that were already cut and finished. If I was doing this today, I would just buy some simple trim at the hardware store and make my own frames after cutting through the door. It works either way, but it would probably save you a bit of money to make your own frame around the cat door hole.

How to Install a Cat Door

• Take the door off
• Place door on sawhorses
• Sand any flaking paint
• Degloss and paint door (if needed)
• Place frame on door in spot where you want the DIY cat door to be
• Trace inside the frame to get the smaller dimension of your frame to cut*
• Using a large drill big, drill into the middle of the marked square to start your hole
• Place your jigsaw inside the hole and cut the square out
• Sand any jagged edges
• Nail the frame over the cat door hole in the door on each side of the door
• Sand any other edges
• Fill nail holes and paint

*Tip: Make sure to cut the inside of the picture frame size out not the outside. You want to use the picture frame as your trim.

When I took the door down, it was the perfect time to dress the door casing as well as the door. They both needed some extra love and were both looking pretty dingy. I used my favorite bright white paint, Ultra White by Valspar but had it color-matched to the best wood trim paint I’ve found, Benjamin Moore Advance.

I’ve tried a bunch of different colors of paint and brands, check out my favorite paint colors and more details if you are looking for a go-to color!

Simple DIY Cat Door Cost Breakdown

I paid $14 for two frames and had everything else on hand to do this project. Like I mentioned earlier, I’m pretty sure you could do this project for around $7 if you just bought simple trim and made your own frame. Either way, I think the wood frame looks way better than the kitty flaps that you see on most installed cat doors!

FAQ’s On Interior Cat Doors

Are cat doors a good idea?

Yes! Cat doors are easy to install and allow your cat to get in and out of spaces that would otherwise be unavailable to them.

How hard is it to install a cat door?

Honestly, installing the cat door to basement project was so simple! I’d rank this as an entry-level DIY project. You need to be comfortable taking the door off the hinge and using a few tools but you can do it!

How do you train a cat to go in a cat door?

You can sit on one side of the door with the cat on the other side and call the cat. If the cat doesn’t want to come through, grab a toy or a treat and gently coax the cat through.

How do you make an indoor cat door?

There’s so many different ways of doing this project, you can easily make your own frame instead of buying picture frames. When I did this project, I was completely new to DIYing so I took the picture frame route. It worked great! Now that I have my feet wet, I would probably just make my own frame.

Like I mentioned earlier, this project was done years ago. We’ve recently made some layout changes to our house and put the litter box (which we have this one and love it!) in our laundry room.

And, I can’t let you leave without showing you a picture of our cat. Her name is Kenai.