The system extending the original single function of material requirements planning (MRP) by including higher-level, long term production planning, master production scheduling (MPS), capacity requirements planning (CRP), production control and purchasing. Where the original MRP function strictly generated a materials plan by exploding bills of material, closed-loop MRP creates feedback and interaction by measuring the proposed material plan against longer term production and sales goals, verifying that capacity is available to complete the proposed production, and incorporating date and quantity changes to original plans required by vendors or the production floor.