Material Requirements Planning I (MRP I)

Material Requirements Planning I (MRP I) is a computer-based inventory management and production planning system that emerged in the 1960s. It was one of the first versions of Material Requirements Planning (MRP) systems designed to help manufacturers manage their inventory levels, plan production schedules, and ensure that the right materials are available at the right time for production. MRP I played a pivotal role in revolutionizing production scheduling and Supply Chain Management (SCM) by providing a more systematic and data-driven approach to manage material requirements.

Key Features of Material Requirements Planning I (MRP I)

  1. Bill of Materials (BOM): MRP I utilizes the Bill of Materials, which is a comprehensive list of all the raw materials, components, and sub-assemblies required to produce a finished product.
  2. Inventory Control: MRP I helps in monitoring and controlling inventory levels by calculating the quantities of materials needed for production and comparing them with existing inventory levels.
  3. Lead Time Calculation: The system considers the lead time required to procure materials and produce finished goods, ensuring that materials are ordered with sufficient time for production.
  4. Production Scheduling: MRP I generates production schedules based on the availability of materials, capacity constraints, and delivery requirements.

Operation of Material Requirements Planning I (MRP I)

  1. Master Production Schedule (MPS): The MPS provides a schedule of finished products to be produced over a specific period.
  2. BOM Explosion: The BOM is “exploded” to calculate the quantities of raw materials and components needed to fulfill the requirements specified in the MPS.
  3. Netting: MRP I calculates net requirements by considering the demand from the MPS and subtracting any existing inventory or scheduled receipts.
  4. Order Generation: Based on net requirements, MRP I generates purchase orders or production orders to ensure that materials are procured or produced in a timely manner.

Benefits of Material Requirements Planning I (MRP I)

  1. Improved Inventory Management: MRP I helps maintain optimal inventory levels by ensuring that materials are available when needed, reducing carrying costs and stockouts.
  2. Enhanced Production Scheduling: With a systematic approach to production scheduling, MRP I helps manufacturers plan and meet production targets more effectively.
  3. Minimized Material Shortages: By calculating material requirements and lead times, MRP I minimizes the risk of material shortages that can disrupt production.

Challenges of Material Requirements Planning I (MRP I)

  1. Data Accuracy: MRP I relies heavily on accurate data, and any errors or inaccuracies can lead to incorrect production schedules and material orders.
  2. Complexity: MRP I can be complex to implement and maintain, requiring skilled personnel and robust software systems.


Material Requirements Planning I (MRP I) was a groundbreaking advancement in inventory management and production scheuling, providing manufacturers with a systematic approach to managing material requirements. By utilizing BOMs, calculating net requirements, and generating production schedules and purchase orders, MRP I helped optimize inventory levels, minimize material shortages, and enhance production scheduling. While newer versions of MRP systems have since evolved, MRP I played a crucial role in laying the foundation for modern production scheduling and Supply Chain Management (SCM) practices.


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