MRP (Material Requirements Planning) is a process that calculates the quantity and timing of material requirements based on the demand and supply situation. MRP performs a net requirement calculation for each material, which compares the available stock and the planned receipts with the requirements and the planned issues. MRP takes into account the following elements during net requirement calculation:
Safety stock: The minimum quantity of material that should be maintained at all times to avoid stockout situations due to unforeseen fluctuations in demand or supply. MRP considers the safety stock as a requirement and tries to replenish it whenever it falls below the defined level.
Purchase orders: The confirmed orders from external vendors that are expected to be delivered within a certain time frame. MRP considers the purchase orders as planned receipts and reduces the net requirement by the quantity and date of the purchase orders.
MRP does not take into account the following elements during net requirement calculation:
Forecast key figures: The projected demand for a material based on historical data, trends, and other factors. MRP does not consider the forecast key figures as requirements, but as a basis for creating planned independent requirements, which are then considered as requirements.
Maximum stock level: The maximum quantity of material that should be maintained at any time to avoid overstocking and excess inventory costs. MRP does not consider the maximum stock level as a constraint, but as a target value for the lot-sizing procedure, which determines the optimal quantity and frequency of replenishment orders.
References: [SAP S/4HANA Production Planning and Manufacturing Certification Guide], page 86; [SAP Help Portal: Net Requirements Calculation].