Abstract: A method for determining bag size to adequately accommodate a food product filled into a ba y a form and fill machine, and subsequently determining the appropriate case pack configuration. The method efficiently and accurately determines a bag size that is large enough to accommodate the product that falls into the bag without interfering with the sealing process of the bag and while determining the appropriate amount of fill within the bag. The method uses various empirically determined relationships from historical bag sizing trials for a specific product and applies these relationships to a series of models in order to solve for a bag length. The method eliminates the need for costly and time-consuming bag sizing trials.