In quilting, overage refers to an amount of fabric that hangs over the edge. Overage is typically necessary when quilting the quilt in order to attach the quilt to a frame and to account for the shifting that takes place as the stitching is performed. Typically, a long arm quilter will want you to have at least 4″ overage on all sides for your backing, so when calculating your backing, you would add 8″ overage into your calculation.
If you are sending a quilt off to be professionally quilted, it is always a good idea to ask your Long armer how much overage they require for backing and batting.
