The fabric required to make a plain zipped cushion is very easy to calculate.
- You will need 2 fabric panels each the same size and shape as the cushion pad
eg: For a 46cmx46cm cushion pad you will require 2 (46cmx46cm) fabric panels, there is no seam allowance as the cover will be slightly smaller than the pad to ensure it fits snuggly and is not baggy.
- With a patterned fabric you may want to position your pattern in a certain place on the cushion cover. (this may require extra fabric)
- You may want the back of the cushion to be a different fabric to the front. (you need the same sized panel for front and back)