<![CDATA[This study developed an integrated decision support framework that linked gypsum demand forecasting with the Economic Order Quantity (EOQ) and Periodic Order Quantity (POQ) inventory control methods. Historical gypsum consumption data from PT Lafarge Cement Indonesia for 2023–2024, together with ordering costs, holding costs, and replenishment lead times, were analyzed to develop an inventory planning strategy for 2025. Three forecasting methods quadratic, exponential, and cyclical forecasting were evaluated using Mean Absolute Percentage Error (MAPE), and the model with the lowest MAPE was selected to estimate future gypsum demand. The results showed that the selected cyclical forecasting method predicted an annual gypsum demand of 73,167.64 tons for 2025. Under the existing inventory policy, the total inventory cost was Rp6,475,551.63. The EOQ model yielded an optimal order quantity of 6,233 tons and a total inventory cost of Rp5,297,287.41, representing savings of Rp1,178,264.22, or 18.20%. The POQ model resulted in a replenishment interval of approximately 1.02 months, with a safety stock of 15,712.24 tons and a reorder point of 22,475.05 tons. This approach resulted in a total inventory cost of Rp5,239,614.91. Compared with the existing policy, the POQ model provided estimated savings of Rp1,235,936.72, equivalent to a 19.09% reduction in inventory costs. These findings demonstrated that integrating demand forecasting with EOQ and POQ provided a practical approach to improving gypsum inventory planning, reducing inventory costs, and maintaining material availability in cement manufacturing.]]>
