I love the Quilter's FabricCalc. I don't know what I would do without it. In fact, when I forget to take it with me to the quilt shop, I'm absolutely lost! It has so many things you can do with it to help determine yardages for designing your own quilts. You can enter the dimensions of your quilt, what size binding and borders you want, and it will tell you how much yardage you need, how many strips to cut, and what width. You can also enter costs of fabric, how much you need of each, and it will calculate how much your total fabric bill will be. If you forget how to use it, the instruction manual fits inside the calculator in a hidden pocket! Mine actually came with a DVD that showed exactly how to use all the functions with great detail and examples. Definitely worth the money to purchase one of these in my opinion.