Remove old covers from sofa cushions.
Fold new fabric in half, right sides of the fabric together. Pin the edges together. Place fabric on a table or other flat surface.
Lay cushion on the fabric.
Trace around the outer edge of the cushion using a fabric marker. Remove sofa cushion from fabric.
Measure and mark 5/8 inch out from marked line all the way around it.
Cut out the fabric on the outer line. These are the top and bottom of your new sofa cushion cover.
Measure the depth of your sofa cushion. Measure around the outer edge of the sofa cushion. Cut a strip of fabric that is as wide as the depth of your cushion plus 1 and ¼ inches and as long as the measurement around the cushion plus 4 inches.
Fold the ends of the strip of fabric under ½ inch twice and iron.
Pin the edges of the strip of fabric to the edges of the top of your new sofa cushion cover, right sides together. Start pinning with the center of the sofa cushion cover top matched to the center of the strip. The strip will overlap itself by about 2 inches when you finish pinning. Repeat this for the bottom of the sofa cushion cover.
Place a pin ½ inch from each corner on the back of the bottom edge.
Sew the top edge of the sofa cushion cover to the strip of fabric using a sewing machine and 5/8 inch seam allowance.
Stitch the bottom edge of the sofa cushion cover to the strip of fabric on the sewing machine with a 5/8 inch seam allowance. Start at one pin that is ½ inch from the corner and stop at the other. This will leave the opening you need to be able to put the cushion inside the cover.
Press all of the seams open, clipping the corners and curves with scissors as needed.
Apply hook and loop tape or insert the zipper into the opening of the back of the cushion cover, following the manufacturer’s directions.
Turn the cover right side out. Press the seams open from the outside.
Insert cushion into cover.
Repeat these steps for each sofa cushion.