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! Plus, see 8 other ideas for interior cat doors.

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 let our kitty get to the basement somehow without leaving the door to the basement open all the time.

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 indoor 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 kitty 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 kitty 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 bit, 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!

Cost breakdown for cat door for interior door

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!

Considering this project? Here’s some FAQ’s:

Is an interior cat door a good idea?

Yes! An indoor cat door is easy to install and allows 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 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 use an interior 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 a DIY 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. But, I do want to share some other options with you and some are easier than other’s to implement.

10 Options for Cat Doors for Doors

Some of these options require a higher skillset with woodworking and other’s not so much. Also, some are using a pre-bought insert and other’s are completely DIY. I wanted to round up a bunch of options for you to consider!

Style 1: Wood Cat Door for Door

This cat door interior door shows wood with a kitty flap. I love how seamlessly the wood blends together and provides interest and almost making it look like it’s a return vent.

Style 2: A literal cat door within a door

I think in some cases it would be nice to be able to close off the cat hole door and this example is a perfect example of how to do that.

Style 3: Cat door for interior door on closet

Oftentimes, we see a larger interior door with cat door as our options for installation so I love being able to show you an example of a built-in closet with an opening for a cat.

Style 4: Hidden Cat Door Interior Door

I hate to choose a favorite option but I’m going to do it and this one is the winner. I just love how this looks! If you have raised panel door, install this one and let me know how it goes.

Style 5: Kitty Head

There are lots of styles of inserts that are shaped like cat heads that you can buy to transform one of your doors like this option. It’s a cute option for a mudroom or closet!

Style 6: Unique Under Stair Idea

I’ll be the first to admit that utilizing under stair storage can be challenging and that’s why I think adding a kitty door here works so well!

Style 7: Cat Door Interior Cabinet Option

How chic is this option? When people get creative and knock something out of the park… I just love it!

Style 8: Cat door for wall

I know we’ve mainly been talking about adding cat doors for interior doors but I do want to share that there are many examples (and this is a good one) of adding a cat door in a wall. I can think of few situations where it would be less noticeable to have one in your wall than a cat hole door in a more visible location.

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.