Measure your bench and cut fabric to size

Start by measuring the top surface of your bench where the cushion will sit. Measure the length, width, and depth you want the cushion to be. Most bench cushions are 4 to 6 inches thick, but you can make yours thinner or thicker depending on comfort and how much foam you have. Write down all three measurements.

For the fabric, you need two pieces: one for the top and one for the bottom. Cut each piece 1 inch larger on all sides than your final cushion size — this extra inch is your seam allowance. If your bench is 36 inches long and 15 inches wide, and you want a 5-inch-thick cushion, cut two fabric rectangles that are 38 inches by 17 inches.

You will also need four strips of fabric for the sides. Each strip should be as long as the perimeter of your cushion (the distance around it) plus 2 inches, and as wide as your cushion thickness plus 2 inches for seam allowance. For a 36-by-15-inch cushion that is 5 inches thick, your side strips would each be about 103 inches long and 7 inches wide.

Key Takeaways

  • Measure your bench carefully and add 1 inch on all sides for seam allowance before cutting fabric.
  • You will need two main fabric pieces (top and bottom) plus four side strips, plus foam or batting to fill the cushion.
  • Sew the side strips to the top and bottom pieces first, then sew three sides closed, insert the foam, and hand-stitch the opening shut.
  • Use a sewing machine for straight seams and a needle and thread for closing the opening by hand.
  • Prewash your fabric if it is cotton, because it will shrink slightly when you wash the finished cushion later.

Prepare your foam and batting

Bench cushions are usually filled with high-density foam, which you can buy at fabric stores or online. Buy a piece that matches your cushion's length, width, and thickness. You can also use multiple layers of batting (the fluffy material used in quilting) if you prefer a softer, less structured cushion.

If your foam is slightly larger than your measurements, trim it with a serrated knife or an electric carving knife. Make clean, straight cuts so the foam sits flat inside the finished cushion cover. Wrap the foam in a layer of batting if you want a softer surface against the fabric.

Sew the side strips to the top piece

Lay your top fabric piece flat, right side up. Take your first side strip and place it right side down along one long edge of the top piece, aligning the raw edges. Pin the strip in place every few inches. Sew along this edge using a straight stitch and a 1-inch seam allowance — this means the needle runs 1 inch from the edge of the fabric.

Repeat this step for the other three sides, sewing one strip to each edge of the top piece. When you sew the corners, the strips will overlap slightly; fold the overlapping ends under at a 45-degree angle and sew them together neatly. Press all the seams flat with an iron when you finish.

Attach the bottom piece and sew three sides closed

Now you have the top piece with all four side strips attached. Lay this assembly flat with the side strips pointing outward. Place your bottom fabric piece on top, right side down, so the right sides of the top and bottom pieces face each other. Pin the bottom piece to the outer edges of the side strips all the way around.

Sew the bottom piece to the side strips using a 1-inch seam allowance, but leave one long side completely open — this is where you will insert the foam. Sew the other three sides completely closed. Trim the corners at a 45-degree angle to reduce bulk, then turn the entire cushion cover right side out through the open side. Use a blunt tool like a wooden spoon handle to push the corners out so they are sharp and square.

Insert the foam and close the opening by hand

Slide your foam (wrapped in batting if you chose to do so) through the open side of the cushion cover. Arrange it so it sits evenly inside and fills all the corners. The foam should fit snugly but not so tight that it stretches the fabric.

Fold the raw edges of the opening inward by 1 inch on both sides and pin them together. Thread a needle with thread that matches your fabric. Use a ladder stitch (also called a slip stitch) to close the opening: bring the needle out through the fold on one side, cross over to the opposite fold, go in and come back out about 1/4 inch away, then cross back to the first side and repeat. This stitch is nearly invisible when done correctly. Knot the thread on the inside when you reach the end.

Press and finish your cushion

Once the cushion is closed, lay it flat and press it gently with a warm iron to smooth out any wrinkles. Do not press directly on seams if your fabric is synthetic, because heat can melt it. Let the cushion sit for a day so the foam settles into its final shape.

Place the cushion on your bench and check how it looks and feels. If you want a firmer cushion, you can add a second layer of foam inside. If you want it softer, you can add more batting around the foam before closing it up.

Care for your finished cushion

Bench cushions collect dust and can absorb spills, so plan to clean yours regularly. If your fabric is washable, you can remove the cushion and spot-clean it with a damp cloth and mild soap. For deeper cleaning, some cushion covers can be unstitched, removed, and machine-washed — but this is a bigger project, so make sure your seams are strong before you try it.

If your cushion will sit outside or in a damp area, consider using outdoor fabric, which resists mildew and fading. Outdoor foam is also available and holds up better to moisture than standard foam.

Frequently Asked Questions

Can I use a sewing machine for the ladder stitch, or do I have to hand-sew the opening?

You have to hand-sew the opening. A ladder stitch is designed to be nearly invisible, and a sewing machine cannot replicate that. Hand-sewing takes 15 to 30 minutes depending on the length of your opening, but the result looks much neater than a machine-sewn seam.

What if my fabric is stretchy or slippery?

Use a walking foot on your sewing machine if you have one — it feeds stretchy fabric evenly and prevents puckering. For slippery fabrics like satin or silk, pin more frequently and sew slowly. You can also use tissue paper under the fabric as you sew and tear it away afterward.

Do I need to prewash the fabric before I start?

If your fabric is cotton, yes — prewash it in warm water and dry it on medium heat to shrink it before cutting. This prevents the finished cushion from shrinking unevenly when you wash it later. Synthetic fabrics usually do not shrink, so prewashing is optional for those.

How thick should the foam be?

Most bench cushions use 4- to 6-inch foam, which provides comfortable support without being too bulky. Thinner foam (2 to 3 inches) works for decorative cushions that do not need much padding. Thicker foam (8 inches or more) is very firm and takes up a lot of space.

Can I make a cushion with a zipper instead of hand-sewing it closed?

Yes. Install a zipper along one side before you sew the bottom piece on. This makes the cover removable for washing, but it adds complexity to the sewing and is visible on the finished cushion. Hand-stitching is simpler for a first project.