Things You'll Need
Whether you have a spare king size comforter or there is only a king size available of your desired comforter, altering the comforter to a twin-sized fit is possible. A king-sized comforter is 102 inches by 86 inches, while a twin is 68 inches by 86 inches. Cutting the width of king-sized comforter will create a twin-sized comforter.
Lay your comforter on a flat surface. Working with the full dimension spread out will make the process quicker.
Measure the dimensions of the comforter to determine the width and length. The width will measure longer than the length.
Measure 69 inches of the width and mark it with a piece of adhesive tape. Tape will not stain the comforter as a permanent marker would.
Place the tape vertically on the area you marked previously, extending it from one end to the other.
Cut along the edge of the tape using sewing scissors. Move carefully to reduce straying away from the tape edge.
Remove a half inch of the cotton from the side. Use scissors for this process to reduce unevenness.
Fold the raw edges inward a third of an inch and form a crease. This will hide the rough edges and give the comforter's seam a finished look.
Begin a weaving process starting at the top of the newly cut comforter using your sewing needle. Stick your thread through the sewing needle hole and tie a knot. Stick the needle through both ends of the cut edge of the comforter and pull the needle through to create a stitch. Continue to stitch the comforter, avoiding the cotton.