The Business Central planning worksheet

The planning worksheet is Business Central's MRP engine. It calculates net requirements for every planning-relevant item across your locations and proposes the orders needed to keep supply aligned with demand. Properly configured, it's the difference between firefighting shortages and running a calm supply chain.

Inputs

The engine considers all supply and demand signals. Supply: on-hand inventory, open purchase orders, open production orders, open transfer orders, planned orders inside the planning horizon. Demand: open sales orders, service orders, components in production orders, transfer requirements, forecast lines, blanket sales orders, and projected demand from job tasks.

Reordering policies

Each item card sets a reordering policy that drives planning behaviour:

• Lot-for-Lot — plan exactly the quantity required by demand on each date.
• Fixed Reorder Qty — order in fixed lots (e.g. carton of 24).
• Maximum Qty — top up to a maximum when below reorder point.
• Order — plan only on direct customer demand (true MTO).

Lead times, safety stock, safety lead times, minimum order quantities, lot multiples, and order modifiers fine-tune the suggestions.

Choosing the policy is the design decision that matters most, and the defaults people reach for are often wrong. Lot-for-Lot suits items with lumpy, order-driven demand; Fixed Reorder Qty and Maximum Qty are reorder-point policies that ignore future demand timing and only look at whether stock has dipped below a threshold — fine for cheap C-class items, dangerous for anything with long lead times or real seasonality. A common failure mode is setting reorder-point policies on everything because they feel intuitive, then wondering why the worksheet suggests purchases for items with no upcoming demand. If demand differs per warehouse, plan per location with stockkeeping units, which let the same item carry different policies, lead times, and replenishment sources (purchase here, transfer there) at each location.

Planning worksheet vs requisition worksheet

BC ships two worksheets. The requisition worksheet handles purchase and transfer replenishment only — no production orders — and suits distribution businesses that buy and move stock. The planning worksheet is the full MRP engine covering production, purchase, transfer, and assembly. Manufacturers live in the planning worksheet; pure wholesalers can stay in the simpler requisition worksheet and avoid maintaining manufacturing-grade item setup. Running both against overlapping item sets is a recipe for duplicate suggestions — pick one home per item.

Running the worksheet

A planner opens the planning worksheet, sets a date range and a filter, and runs Calculate Regenerative Plan or Calculate Net Change Plan. Regenerative recomputes from scratch; net change updates only items affected by changes since the last run. The output is a list of suggestions — new purchase orders, production orders, transfer orders, plus reschedule and cancellation actions on existing orders.

Acceptance

Planners review suggestions and accept them with the Carry Out Action Message function, which creates or modifies the suggested supply orders. Accepted suggestions disappear from the worksheet.

Action messages

New, Change Qty, Reschedule, Reschedule & Change Qty, Cancel — each indicates what the engine wants you to do, with reasons (early supply, late supply, demand changed, etc.).

Subcontracting and assembly

Subcontracted production operations auto-suggest purchase orders to the subcontract vendor; assembly items can use a simpler assembly planning routine — see assembly orders in Business Central for when that routine fits better than a full production order.

Rolling it out without chaos

The worst way to adopt the planning worksheet is to configure every item and run a regenerative plan across the whole catalogue on day one — the result is thousands of suggestions nobody trusts, and the tool is abandoned within a month. The rollout that works:

• Start with one item class — a supplier's range, or the A-items at one location — and run the worksheet daily for a few weeks until the suggestions match what a good planner would have done by hand.
• Fix master data before blaming the engine. Wrong lead times, missing vendor catalogues, and stale safety stock produce wrong suggestions with perfect logic. The worksheet is a master-data quality audit whether you want one or not.
• Use the dampener settings (dampener period and quantity on the item card) to suppress trivial reschedule messages — a suggestion to move an order by one day creates noise, not value.
• Never carry out actions unreviewed. The worksheet proposes; the planner disposes. Automating Carry Out Action Message end-to-end is tempting and almost always premature.

A worksheet nobody trusts gets bypassed with manual purchase orders — which then appear as unexpected supply in the next run, making the suggestions stranger and trust lower. The loop only stabilises when planners work through the worksheet, exceptions included.

Where it stops

The engine is single-level per run in its reasoning about capacity and is not finitely capacity-constrained — it will happily load 300 hours of production onto a work centre with 80 available. Capacity checking happens downstream, on the production orders it creates. For demand sensing, finite scheduling, complex scenario planning, or full S&OP, customers add an ISV planning module or step up to Dynamics 365 Supply Chain Management, whose Planning Optimization service is built for exactly that scale. For the production side of what the worksheet feeds, see Business Central manufacturing.