MRP II — Manufacturing Resource Planning
MRP II (Manufacturing Resource Planning) is the 1980s evolution of MRP (Material Requirements Planning), extending material planning with capacity planning, financial accounting integration and shop-floor control. MRP II established the blueprint for modern ERP: integrate production planning with financial and operational data into one coherent system. While the term MRP II has been largely subsumed by ERP, the concepts and implementation methodology remain influential in manufacturing-centric operations.
Evolution from MRP to MRP II to ERP
MRP (1970s): calculate material requirements from MPS and bills of materials. Limited to material planning only; assumes infinite capacity. MRP II (1980s): extends MRP with capacity requirements planning (CRP) for machines and labor, shop-floor control for work-order release and progress tracking, cost accounting integration linking production to financial results, master production scheduling (MPS) as the formal demand-to-supply bridging mechanism. ERP (1990s): extends MRP II beyond manufacturing into HR, sales, purchasing, project management, basic CRM — creating the integrated enterprise system. Each step preserved the previous functionality; MRP II is a subset of modern ERP rather than a separate category.
Classical MRP II components
- Business plan (long-term, 3-5 years) — strategic capacity and investment plan
- Sales and Operations Planning (S&OP) — aggregate demand-supply reconciliation, monthly
- Master Production Schedule (MPS) — finished-goods production plan, weekly or daily
- Material Requirements Planning (MRP) — component and raw-material requirements explosion
- Capacity Requirements Planning (CRP) — machine and labor capacity verification against the plan
- Shop floor control — work-order release, progress reporting, completion confirmation
- Production reporting — performance feedback into the planning cycle
MRP II in modern ERP
Modern ERPs (SAP S/4HANA, Microsoft Dynamics 365 F&O, Oracle Cloud ERP, Infor CloudSuite/M3, Epicor Kinetic, NetSuite, Acumatica) implement MRP II concepts natively. Users typically do not encounter the term 'MRP II' in the modern UX; the underlying functionality (MPS, MRP, CRP, shop-floor control) is present and configurable. APS (see APS) extends MRP II by adding finite-capacity scheduling. Modern AI-driven forecasting and machine-learning anomaly detection layer on top of the classical MRP II foundation. For manufacturing-centric ERP selection, understanding the MRP II foundations remains useful even though the terminology has shifted.
Limitations and modern alternatives
Classical MRP II assumes deterministic processes with stable demand, predictable lead times and infinite capacity at planning level. Real-world manufacturing violates all three. Modern improvements address these. APS replaces the infinite-capacity assumption with constraint-based scheduling. Demand sensing and ML forecasting reduce reliance on stable forecasts. Real-time event streaming from MES, IoT and supply-chain visibility platforms enables faster reaction to deviations. Pull-based replenishment (kanban, demand-driven MRP) complements push-based MRP for high-volume stable-demand parts. US mid-market manufacturers typically combine these techniques: MRP for materials, APS for scheduling, kanban for high-velocity parts, demand sensing for forecast improvement.