I saw the easiest method from Bonnie K Browning ever of calculating scallops. All you do is take a piece of adding paper (available at dollar store) and cut/tear it the length of your quilt - 1/2". Then you just fold it in half. Open it up & then fold each edge to the middle. Open that up & fold each of the lines so it touches the next & crease. When the creased boxes are about the right size that you want for your scallops, that's how wide you make them.
You open & fold edge to middle & such rather than just folding & folding & folding because opening & folding to the crease is more precise.
Once you know your finished measurement, just add 1/2" for seam allowances.
Last edited by Bree123; 06-05-2016 at 04:00 AM.