I've been trying out different types of cushion covers lately..
Super secure and real nice fit. The pillow form measure 20"X20" which I got for $4.90 from Ikea. The pillow form is quite loosely filled so when I cut the fabric, I use 20" square so that it will be more form fitting. I love how this one looks so cheery and bright.
Invisible Zipper closure
The zipper closure is applied to the bottom of the cushion cover before I sew up the 3 sides. For the front, I join the 2 fabric together and sew a piece of red satin ribbon over the seam line for added interest. This one is so sweet.
This is a 14" pillow form from Ikea. It's a steal at $1.90 each. The pillow form is more tightly packed, so for this one, I cut the fabric with 1/4" seam allowance. Also, with envelope closure, if you sew the cover too tightly, the back will not lay flat.
Sewing cushion covers are so easy and quick. I sew up the 3 covers in just a night of sewing, including cutting. I think I prefer the zipper closure because it is really neat and so easy to change the pillow. Which do you prefer?