The Basic Steps for Adding a Zipper to a Cushion Cover

A zipper cushion cover is sewn almost like a regular cover, but you insert the zipper into one seam before closing the cover completely. The zipper goes on the back panel, running edge to edge, so you can remove and wash the cover without unpicking seams. You sew three sides normally, attach the zipper to the opening, then stitch the fourth side closed around it.

The process takes about two to three hours for a beginner, depending on cushion size. You will need a sewing machine, a zipper (usually 16 to 24 inches for standard cushions), two pieces of fabric cut to size, thread, pins, and a zipper foot attachment for your machine.

Key Takeaways

  • Cut your fabric pieces the same size as your finished cushion, plus half an inch on all sides for seam allowance.
  • Sew the front and back panels together on three sides with a half-inch seam, leaving one side open for the zipper.
  • Pin the zipper face-down along the open edge, with the zipper teeth aligned to your seam line, then stitch it down using a zipper foot.
  • Fold the fabric over the zipper and stitch the final seam, which closes the cover and secures the zipper in place.
  • Turn the cover right-side out through the zipper opening, insert your cushion, and zip it closed.

Cutting Your Fabric to the Right Size

Measure your cushion form in length and width. Add one inch to both measurements — half an inch on each side for seam allowance. If your cushion is 16 by 16 inches, cut two pieces of fabric 17 by 17 inches. Use a ruler and fabric pencil or chalk to mark your cutting lines, then cut straight with sharp fabric scissors.

Lay both pieces on top of each other with the right sides (the pretty sides) facing each other. This is called "right sides together" and is the standard position for sewing seams that will be hidden when you turn the cover right-side out later. Pin the layers together so they do not shift while you work.

Sewing Three Sides Before the Zipper

Thread your sewing machine and set it to a straight stitch with medium length (about 2.5 on most machines). Start at one corner of your pinned fabric. Sew along one long side with a half-inch seam allowance — that means the needle should be half an inch away from the fabric edge. Backstitch at the start and end to lock the thread.

Continue around two more sides, sewing the full length of each and backstitching at each corner. Stop when you reach the fourth side — this is where your zipper will go. Leave this side completely unsewn. Remove the pins and press your three sewn seams flat with an iron to make them crisp.

Preparing and Pinning the Zipper

Lay your fabric flat with the unsewn side facing you. Open your zipper all the way. Place the zipper face-down (teeth pointing toward the fabric) along the open edge, with the top stop of the zipper aligned to one corner of your seam line. The zipper tape — the fabric strip on either side of the teeth — should sit exactly on your half-inch seam line.

Pin the zipper in place along both long edges of the tape. Make sure the pins go through the zipper tape and both layers of your cushion fabric. The zipper should be centered on the opening, with equal fabric extending beyond it on both sides. If your zipper is shorter than your opening, that is fine — the fabric will overlap at the corners.

Stitching the Zipper Down

Attach the zipper foot to your sewing machine. This is a special presser foot that sits closer to the needle than a regular foot, so you can stitch right next to the zipper teeth without hitting them. Consult your machine manual if you are unsure how to attach it — the method varies by brand.

Sew along one side of the zipper tape, staying as close to the teeth as your foot allows. Backstitch at the start and end. Then flip the fabric over and sew along the other side of the zipper tape the same way. You should now have the zipper stitched firmly to both layers of fabric along both edges of the tape.

Closing the Cover Around the Zipper

Switch back to your regular presser foot. Close the zipper most of the way — leave it open about two inches so you can turn the cover right-side out later. Fold the fabric edges of the opening over the zipper, so the raw edges meet and the zipper is sandwiched between them. Pin along the entire opening.

Sew the final seam with a half-inch allowance, stitching all the way across the opening. This seam will be on top of the zipper, so sew slowly and carefully. Backstitch at both ends. You have now sewn all four sides closed, with the zipper built into one of them.

Turning and Finishing Your Cover

Trim the corners of your fabric diagonally, cutting away the corner triangles about a quarter inch from the seam. This reduces bulk when you turn the cover right-side out and makes the corners sit flat. Do not cut into the seam itself.

Reach through the zipper opening and grab the fabric from inside. Pull the entire cover through the opening, turning it right-side out. Use a blunt tool like a chopstick or point turner to push the corners out fully so they are sharp and square. Press the entire cover with an iron, paying special attention to the seams and the zipper edge.

Insert your cushion form through the zipper opening and zip the cover closed. If the zipper is stiff, run a pencil along the teeth a few times to loosen it.

Frequently Asked Questions

What size zipper do I need for my cushion?

The zipper should be about one inch shorter than the side it is going into. A 16-inch cushion needs a 14 or 15-inch zipper. Zippers come in standard lengths like 12, 14, 16, 18, 20, and 24 inches, so measure your finished cushion width and pick the next size down.

Can I put the zipper on a different side?

Yes. The zipper is usually placed on the back so it is less visible, but you can put it on any side. Some people put it on a bottom corner instead of a full side, which uses a shorter zipper. The sewing method stays the same.

What if my zipper is too short for the opening?

The fabric will overlap at the corners, which is normal and fine. Sew the overlapped corners closed by hand with a ladder stitch (also called a whip stitch) after you turn the cover right-side out. This creates an invisible seam and holds the corners neatly.

How do I fix a zipper that got sewn crooked?

If the zipper is slightly off-center but still functional, leave it as is — it will not affect the cover's use. If it is so crooked that the cover will not close evenly, you can carefully cut out the old zipper stitches with a seam ripper and re-stitch it. This takes patience but is fixable.

Do I need a special zipper foot for my machine?

Most sewing machines come with a zipper foot or one is inexpensive to buy separately. Check your machine manual to see if you have one. If your machine did not come with one, search for your machine model and "zipper foot" — they are universal and cost five to fifteen dollars.