MRP is short for Materials Requirements Planning and it is a production planning technique that’s used to manage the manufacturing process. It is basically used to determine your Material Planning procedure by specifying the various conditions like Reorder Point, Seasonal Requirement, Replenishment, Vendor Managed, Forecast Based and Master Production Scheduling (MPS). Lot size specifies the nature of material requirement in terms of Weekly, Monthly, Quantity and Maximum Replenishment.