My DH has an iPhone. And he found this wonderful quilt app for me. The QuiltFab App helps you calculate how much fabric you need for a project. I have used it twice to calculate how much fabric I should buy for the boarders, binding, and backing of a quilt. It works great. You can change the settings to calculate exactly how much fabric you need without any waste. If you don't have an iPhone (such as myself) you can email the calculations to yourself. Then you can take them to the sewing store with you.