What Is MRP II?
Also known as: Manufacturing Resource Planning, MRP2
Definition
MRP II (Manufacturing Resource Planning) is the closed-loop extension of MRP that adds capacity planning, shop floor control, purchasing execution, and financial simulation, so the material plan is validated against labor, machine, and money constraints before release.
MRP II Explained
MRP II emerged in the early 1980s as practitioners hit the limits of pure material planning. The insight was that a material plan nobody can execute is not a plan. MRP II therefore wraps the MRP calculation in a loop: business planning sets the financial envelope, sales and operations planning sets volume by family, the master production schedule sets buildable end items, MRP explodes materials, and capacity requirements planning checks whether the resulting load fits available hours. Feedback from the shop floor closes the loop back to the schedule.
The closed-loop element is what distinguishes MRP II from MRP. In a true closed loop, shop floor reporting of completions, scrap, and actual run times feeds back into the next planning cycle, and rough cut capacity planning is used to reject an infeasible master production schedule before it reaches MRP. Systems that only push plans downward without ingesting execution reality are running MRP with extra screens, not MRP II.
MRP II also introduced the idea that operational plans and financial plans should be the same plan expressed in different units. The production schedule stated in units, when costed, becomes the projected cost of goods sold; the purchase plan becomes projected payables. This is the direct ancestor of the integrated ERP ledger, and it is why simulation capability, sometimes called what-if planning, is treated as a core MRP II function rather than a reporting extra.
In modern ERP the MRP II label has largely been absorbed by ERP itself. Infor SyteLine, LN, and M3 all implement the full closed loop, and the terminology survives mostly in APICS and CPIM training material. The concepts remain load-bearing though: when a plant complains that ERP is disconnected from reality, the diagnosis is nearly always a broken feedback leg in the MRP II loop.
Why It Matters
- Closing the loop with shop floor feedback is what keeps planned dates credible instead of drifting into fiction within weeks.
- Capacity validation before MRP prevents the plant from being handed a schedule that guarantees late orders.
- Expressing the operational plan in dollars lets finance and operations argue from one number rather than two.
- MRP II discipline is the foundation auditors and CPIM-certified planners expect, and it shapes how ERP modules are configured.
In Practice
The most common failure is a master production schedule that is never rejected. If rough cut capacity planning shows 140 percent load on the bottleneck and the schedule is released anyway because sales committed the dates, the loop is open. Enforce a written rule that a master production schedule over a defined load threshold must be rebalanced or escalated before MRP is allowed to run against it.
Frequently Asked Questions
How is MRP II different from ERP?
MRP II covers manufacturing planning and its financial simulation: business planning, sales and operations planning, master scheduling, MRP, capacity planning, and shop floor control. ERP keeps all of that and adds the enterprise functions MRP II never covered, including full general ledger and subledgers, order-to-cash, procurement, HR, service, and multi-site or multi-currency consolidation.
Is MRP II still relevant with modern scheduling tools?
Yes, because MRP II describes a governance loop, not a specific algorithm. Advanced planning and scheduling engines replace the capacity requirements planning step with finite-capacity math, but the sequence of business plan, sales and operations plan, master schedule, material plan, capacity check, and shop floor feedback is still the structure every discrete ERP is built around.
Related Terms
MRP (Material Requirements Planning)
MRP (Material Requirements Planning) is the ERP calculation that explodes demand through bills of materials, nets it against on-hand and on-order inventory, and offsets by lead time to produce timed purchase and work order suggestions.
Capacity Planning
Capacity planning is the process of comparing the labor and machine hours a production plan requires against the hours each work center actually has available, identifying overloads early enough to reschedule, add shifts, or outsource.
MPS (Master Production Schedule)
An MPS (master production schedule) is the time-phased statement of which end items a plant will produce, in what quantities, and in which periods. It is the anchor demand input MRP explodes into component requirements.
Go Deeper
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