The QDISCX.lng Model Economic Order Quantity View the model Download the model The classic EOQ (Economic Order Quantity) inventory model detailed in every introductory operations research text tells us the optimal order quantity of an item given its demand rate, unit holding cost, and fixed order cost. A common situation not handled by the standard EOQ model is quantity discounts. In this model, we extend the EOQ analysis by allowing for quantity discounts. Keywords: Demand Backlog | Economic Order Quantity | Forecasting | Inventory | Product Management | Production | Reorder Point