Finished my cushions today!

Along with this great tutorial I'm also using a book I got at Joann's. In the book she gives a formula for the band so you don't have extra fabric. Here's what the book says:

For the zipper panel, measure the length of the cushion's existing zipper, from pull to stopper. Add 2". This is the panel cut length. Add 2" to the cushion depth. This is the panel cut depth. Cut one panel in these dimensions.

For the remaining box band panel, measure the remaining cushion perimeter from the zipper pull, around the cushion side, front, and sides edges to the zipper stop; add 5" to this measurement. The resulting figure is the panel cut length. Add 1" to the cushion depth; this is the panel cut depth. Cut one panel in these dimensions.

Also note, with these instructions you create a 1" deep pocket around the zipper on both ends. And seam allowance is 1/2". I used this formula and my band went on perfectly without a single fold or pucker!