You know that feeling when you find the perfect bedding set online, only to open the package and realize the duvet cover is two inches too short for your fluffy comforter? Or maybe you love the fabric of a flat sheet but have zero use for the fitted sheet and pillowcases that came with it. Instead of living with a sagging cover or sending that pretty fabric to the donation pile, you can solve both problems with a single weekend project: sewing your own custom duvet cover from two flat sheets. This is one of those rare home projects that feels both luxurious and thrifty at the same time.

Before you protest that you are not a seamstress, take a deep breath. This project is far easier than hemming a pair of pants or making a dress. The entire process relies on straight seams, and most of your time will be spent measuring and pinning, not sewing. The beauty of using flat sheets is that they already have finished, hemed edges on the sides and bottom, which means you have less work to do. The top edge is the only part you will need to finish, and even that is a simple fold and stitch.

Start by gathering your materials. You will need two flat sheets. They can be the same pattern or coordinating solids. Thrift stores are a gold mine for high-quality, 100 percent cotton sheets that have been worn soft by years of use. If you are buying new, look for a high thread count for the best feel against your skin. You will also need thread that matches your sheets, fabric scissors, straight pins, a measuring tape, and a sewing machine. A basic machine is fine, but make sure you have a universal needle that can handle the fabric weight.

The very first thing you must do is measure your duvet insert. Lay it flat on the floor and measure both the length and the width. Do not rely on the package label because comforters often shift after washing. Add two inches to both the length and the width. This extra inch on each side accounts for the seam allowance and a little wiggle room so your insert slides in easily. Now measure your flat sheets. A twin or full sheet set will give you a smaller cover, while queen and king sheets work for larger beds. If your sheets are too small, you can sew two sheets together horizontally, but for the cleanest look, use sheets that are larger than your duvet insert.

Wash and dry both sheets before you start. This pre-shrinks the fabric so your finished cover will not pucker the first time you launder it. Iron them if you can. Wrinkles make accurate measuring impossible, and you want your seams to be crisp. Lay one sheet on the floor with the right side facing up. Place the second sheet directly on top with the right side facing down. The wrong sides of the fabric should be facing outward. Align the edges as best you can, matching the bottom hems. If your sheets are different sizes, center the smaller one within the larger one.

Pin the two sheets together along the side edges and the bottom edge. You are essentially creating a giant pillowcase. Leave the top edge completely open. Sew a straight stitch along both sides and the bottom, using a half-inch seam allowance. Backstitch at the beginning and end of each seam to lock the threads. After sewing, you have a choice. You can leave the raw edges exposed, but they will fray over time. A better approach is to finish the seam with a zigzag stitch or a serger. You can also use pinking shears to cut the seam allowance, which reduces fraying without adding bulk.

Now you need to close the duvet cover at the top. There are three common methods, and the easiest for a beginner is the button closure. Fold the raw edge of the open top over by a half inch, then fold it over another inch. Pin this hem in place and sew it closed along the inner fold line. This creates a clean, finished edge. Mark where you want your buttons to go, evenly spaced across the top. Sew buttonholes on one side of the open top, then sew the buttons onto the opposite side. If buttonholes intimidate you, use sew-on snaps or a strip of hook-and-loop tape. Another favorite method is adding fabric ties. Cut eight strips of leftover sheet fabric, each about eight inches long and two inches wide. Fold each strip in half lengthwise, sew the long edge, and turn it right side out. Pin four ties to the inside of the top edge on one sheet, matching them with four ties on the other sheet. Tuck the ties inside the cover, sew the top closed, and then use the ties to secure the duvet insert inside. This method looks beautiful and is remarkably functional.

Turn your finished cover right side out. Give it a good shake and slide your duvet insert inside. Smooth it out and button or tie it closed. You have just created a custom bedding set that fits your insert perfectly, matches your taste exactly, and cost a fraction of what a store-bought set would run. Plus, you did it yourself. That is a feeling no department store can replicate.