Measure the width of your door.
Draw a rectangle on the back of your carpet scrap that is as wide as the measurement of your door and 2 feet long. While a door mat can be any size that will lay flat in front of the door, this size works well.
Cut the rectangle out of the carpet by using a utility knife. Turn the carpet right-side up again.
Lay the carpet binding tape flat on the floor. The carpet binding tape has two parts: a flat adhesive part covered with a protective plastic film and a braided bound edge. The adhesive part is meant to be stuck to the bottom of the carpet, while the bound edge sits snugly next to the raw edge of the carpet, giving the carpet its finished edge.
Peel back the protective plastic film, exposing the adhesive.
Bring the edge of the carpet up to the binding tape, laying the edge of the carpet snugly against the bound edge and on top of the adhesive. The binding tape should start at the middle of one of the carpet’s edges.
Bring the carpet and the binding strip together all the way around the carpet, overlapping the adhesive to go around the corners.
Snip off the excess tape, bringing the two ends of the tape snugly together.
Apply a dot of hot glue from a hot glue gun into the crevice between the bound edge and the carpet scrap every 4 to 6 inches to further secure the tape to the carpet. When the glue cures, the rug is ready to be used.