The Effects of Non‐Constant Purchase and Replenishment Costs on the EOQ Model

This paper examines the sensitivity of the Economic Order Quantity (EOQ) inventory model to lot size errors when the purchase cost per unit, C, and the replenishment cost per order, A, are both dependent on the amount ordered, Q. A formula for the percentage increase in average annual variable costs due to using a Q‐value different from Q is derived, and is shown to be the same as that for the simple EOQ and backorders model.