Material Requirements Planning (MRP) is a computer-based inventory management system crucial for production managers. It streamlines scheduling and order placement for dependent demand items—the components necessary to create finished products. Think raw materials, component parts, and subassemblies; their inventory needs directly correlate with the production level of the final product. For instance, a bicycle manufacturer’s dependent demand items include aluminum, tires, seats, and derailleurs.
Early MRP systems emerged in the mid-20th century, leveraging mainframe computers to translate a finished product’s bill of materials into a comprehensive production and purchasing plan. These systems quickly evolved to incorporate feedback loops, enabling production personnel to dynamically adjust system inputs. This advancement paved the way for Manufacturing Resources Planning (MRP II), which broadened the scope to include marketing, finance, accounting, engineering, and human resources. Enterprise Resources Planning (ERP) takes this concept even further, utilizing technology to integrate functional areas across the entire business.
At its core, MRP operates by working backward from a production plan for finished goods. This allows for the precise calculation of requirements for components and raw materials. The system is designed to answer three fundamental questions: What is needed? How much is needed? And when is it needed?
By dividing inventory requirements into discrete planning periods, MRP facilitates timely production while minimizing inventory levels and associated carrying costs. When implemented effectively, MRP empowers production managers to anticipate capacity needs and efficiently allocate production time, optimizing the entire manufacturing process.