Measure the swing's length and depth. Record these measurements, as you will need them twice during the project.
Cut the foam padding to match the swing seat measurements.
Measure the height of the foam. Record it with the measurements you made earlier.
Add 1 inch to the swing measurements. Draw a rectangle to match on the tracing paper or newsprint.
Add half the height of the foam to each side of the pattern rectangle. For example, if you've chosen 2-inch thick foam, add 1 inch to all four sides.
Fold the fabric in half and pin the pattern to it. Cut on the outside line to make two pieces.
Pin the fabric pieces together with the wrong sides facing each other.
Stitch along the two long sides and one short side, using a 1/2-inch seam allowance.
Insert the foam cushion through the open end.
Fold a 1/2-inch seam allowance on the open end to the inside. Hand-stitch the end closed.