Bonnie Hunter's website has a calculator that will give all kind of helpful information. I am going to include the website address here as well as one other and the last one is an app for your phone quiltville.com myquilter.com and the is Robert Kaufman, I just typed in quilting calculator in the play store search. These have come in very handy for me many times, the myquilter one the lady at the quilt shop suggested it as it is what they use in the store.