Glass Cat Door | How to Cut a Round Opening in Glass

August 20, 2016

Tired of your cat scratching your front door and damaging the glass or wood? The solution may be the installation of a glass cat door. Easier said than done, if your front door or back door is also made of glass. No need to worry just watch the video below to see how you can cut a round opening in your glass door.

Glass Cat Door Installation Step by Step Instructions

Carefully remove the glass pane from the door frame so you can lay it flat on your workbench while you make the cut. Be sure to lay a protective pad on your bench so you don’t scratch the glass.

Locate the center point of your door opening and place the cutting tool suction cup on the glass. Set the compass radius to half the diameter of the finish dimensions you are looking for. With the cutting tool in place make one full pass of 360 degrees.

Reset the compass arm about 1” shorter to make a second cut. This inner circle is simply a safety precaution so that you don’t inadvertently break the outer glass when you knock out the center glass.

Use the tips of your fingers to gently tap along the cut line. This will carry the cutline through the glass for full penetration. Be careful not to push too hard, as you don’t want to punch out the hole center just yet.

Remove the cutting tool from the compass and remove the compass from the glass. Using the cutting tool, manually score several lines inside the inner circle. The score marks should be about half an inch apart in both directions to form a grid pattern.

Before you start this next step, make sure you are wearing safety glasses and gloves. Now, holding the glass over a trash can, gently tap on the center circle to knock out all of the glass squares.

Score the remaining ring in 4 locations to break it up into 4 quadrants. Score both the bottom and top of the glass. Score a small “V” adjacent to the quadrant dividing mark. Gently knock out this “V”. You may need to wiggle it back and forth with some needle nose pliers.

Voila! You now have a perfectly round hole in your glass. Now follow the instructions that came with your commercially available cat door to mount it to the glass and your glass cat door is complete.

Watch the Video

Watch this video to learn how to cut a round opening in your glass door so you can install a glass cat door for your favorite pet.

Contact Us:

Do you need custom windows for your home? Contact One Source Renovation, LLC at or give us a call at (815)-634-8922.