Supply Planning: from static MRP to dynamic plan

Reality is different. Demand shifts every week, lead times swing, suppliers delay, raw materials block production, firm orders clash with new priorities. An MRP running once a month is not enough — by the time the result comes out, the world has already moved.

Integrated replenishment is the opposite of that.

It is a living plan, recomputed in minutes, that connects finished-good explosion all the way to the last raw material — respecting what is firm, what is in transit and what each chain constraint allows to be produced.

Planning supply is not about computing requirements. It is about deciding, based on every chain constraint, what to buy, what to produce and when — before the problem happens.

A structured process that starts from consolidated demand, propagates requirements through every BOM level, matches against what is already firm and available, and returns an executable production and purchase plan.

The BOM (Bill of Materials) is the map of what each product consumes. Without it, MRP is just a balance sheet. With it, the system propagates the decision made on the finished good to every component and raw material, automatically.

Each item receives a level: N0 for finished, N1 for intermediates and packaging, N2 (or deeper) for raw materials. At each level the system knows how much of the lower component is consumed, the process loss and the production operation linked to it.

With that structure in place, the system can perform the core MRP operation: walk down the tree. When the planner sets the finished good's Plan, that Plan explodes into Demand for every component on the level below — multiplied by the BOM quantity and adjusted by loss. That is what we'll visualize on the planning grid.

The BOM is not only technical structure. It defines how demand travels through the chain.

The planning grid is the screen where each SKU shows, week by week, what is demanded, what is firm, what the system suggests producing or purchasing, and how projected stock behaves. It is the single view that replaces dozens of parallel spreadsheets.

Below, a real grid example for a finished good. Each column is a week; each row answers a different question about that SKU.

Hover the (i) icon next to each grid row to see the definition of Demand, Scheduled, Plan, Stock, Coverage and Status.

Walking down the structure: the same grid, chained

The grid's power is not in a single isolated screen. It is in seeing, in the same view, the finished good, the intermediate component and the raw material — each with the same set of rows, linked by BOM explosion. The animation below shows how the finished good's Plan becomes the component's Demand, and how the component's MRP responds with its own Plan.

This chaining is what separates an integrated plan from a set of parallel spreadsheets. When a raw material enters risk at the deepest level, the planner sees, on the same screen, which intermediate it blocks, which finished good depends on that intermediate, and which customer is exposed. The decision stops being local and becomes end-to-end.

Gross requirement is the bucket's raw demand. Net requirement is what actually needs to be produced or purchased to replenish stock up to the target, after discounting everything already available or in route.

After that, the engine applies minimum batch, multiple, supplier calendar and production window rules. A 47-unit need for an RM with multiple of 50 and minimum batch of 100 becomes a 100-unit order.

Classic MRP computes requirements. Dynamic MRP computes feasible requirements — testing, in each bucket, whether chain constraints allow that plan.

The feasible plan is not the ideal plan. It is the possible plan, given today's constraints.

Companies with more than one plant typically run separate plans — each plant pulls its material and generates its purchase without a consolidated view. The result is duplicated stock, uncoordinated purchases and last-minute transfers.

Multi-plant planning treats the operation as a single chain with distinct production points. When Plant B needs a component made by Plant A, this becomes automatic demand at A, a scheduled transfer and in-transit stock for B.

Most supply decisions involve trade-offs that look obvious but rarely are. Buy from the cheaper supplier with long lead time, or from the pricier one with fast delivery? Pull production forward to free capacity in peak weeks, or accept stockout risk?

A good supply plan is not born ready. It is born from testing several hypotheses and picking the one that best balances cost, risk and service.

NPLAN solves every one of these challenges in an integrated, automated way — removing the operational burden of running supply planning in parallel spreadsheets.