The Reordering Policy on an item or stockkeeping unit (SKU) determines how Business Central plans replenishment. The Enhanced Planning Worksheet uses the same reordering policy and planning fields when you run Calculate Purchase Plan, but the Purchase Plan calculation is designed to provide a practical purchasing recommendation rather than reproduce the full Business Central planning engine.

Understanding the reordering policies helps explain why a purchase quantity is suggested and which planning fields affect the result.

Reordering policies in Business Central

Business Central provides four reordering policies:

• Fixed Reorder Qty.
• Maximum Qty.
• Order
• Lot-for-Lot

If the Reordering Policy is blank, the item or SKU isn’t included in supply planning. The Enhanced Planning Worksheet follows this principle as well: Calculate Purchase Plan skips SKUs that don’t have a Reordering Policy.

Microsoft provides detailed information about the standard planning behavior in Design details: Handling reordering policies.

Important: The descriptions below distinguish between standard Business Central planning and the Calculate Purchase Plan calculation in the Enhanced Planning Worksheet. Calculate Purchase Plan uses many of the same planning parameters, but doesn’t run the standard Business Central regenerative planning algorithm.

Fixed Reorder Qty.

In standard Business Central planning, Fixed Reorder Qty. is intended for inventory that is replenished in relatively consistent quantities. The Reorder Point determines when replenishment is required, and the Reorder Quantity establishes the normal amount to order.

When Calculate Purchase Plan is used, the Enhanced Planning Worksheet considers:

• Current available supply and demand
• Safety Stock Quantity
• Reorder Point
• Reorder Quantity
• Minimum Order Quantity
• Order Multiple

When available quantity reaches the Safety Stock Quantity + Reorder Point, the Purchase Plan calculates a replenishment quantity. It orders at least the Reorder Quantity, increasing the quantity when necessary to restore the required inventory level.

This policy is useful when items are normally purchased in consistent quantities such as cases, pallets, or standard production lots.

Maximum Qty.

The Maximum Qty. policy is intended to replenish inventory toward a specified Maximum Inventory level.

With Calculate Purchase Plan, a purchase is normally triggered when available inventory reaches the Safety Stock Quantity + Reorder Point. The suggested quantity replenishes inventory toward Maximum Inventory while ensuring the reorder point and safety stock requirements are also covered.

The Run Purchase Plan request page also provides the Minimum Level to Trigger Reorder option. When you select Maximum Qty. instead of Reorder Point, the Enhanced Planning Worksheet can replenish inventory whenever it falls below the Maximum Inventory level.

This can be useful when you deliberately want to maintain higher inventory during periods of increased or seasonal demand.

For more information about the Purchase Plan options, see Enhanced Planning Worksheet.

Lot-for-Lot

In standard Business Central planning, Lot-for-Lot groups demand into supply according to planning parameters such as the Lot Accumulation Period. It is commonly used when replenishment should closely follow actual or forecast demand rather than maintaining inventory using a reorder point.

Microsoft describes the standard Lot-for-Lot behavior in Design details: Planning parameters.

Calculate Purchase Plan uses a simpler inventory-oriented calculation. It calculates available quantity after considering applicable supply and demand and suggests enough replenishment to cover any shortage relative to the Safety Stock Quantity.

For example, if calculated availability is -20 and Safety Stock Quantity is 10, Calculate Purchase Plan initially determines that 30 units are required, before applying applicable order modifiers.

A Reorder Point or Maximum Inventory isn’t required for Calculate Purchase Plan to generate a suggestion for a Lot-for-Lot SKU.

Order

In standard Business Central planning, the Order policy is designed around individual demand and supply relationships. Business Central normally creates supply specifically for individual demand rather than using reorder-point inventory planning.

For Calculate Purchase Plan, Order and Lot-for-Lot use the same inventory-oriented replenishment calculation. The Purchase Plan calculates the net available quantity and suggests enough supply to cover a shortage relative to the Safety Stock Quantity.

This means Calculate Purchase Plan can still provide an aggregated purchasing recommendation for an item using the Order policy without reproducing Business Central’s standard order-to-order planning relationships.

Order modifiers

After Calculate Purchase Plan determines that replenishment is required, the Enhanced Planning Worksheet also applies applicable ordering parameters.

Minimum Order Quantity prevents a suggested order from being smaller than the configured minimum.

Order Multiple rounds the suggested quantity upward to the configured purchasing multiple.

For example, if the initial requirement is 63 units and the Order Multiple is 25, the suggested quantity is increased to 75 units.

These fields can be maintained on the Item or SKU and are also described in Microsoft’s Planning parameters documentation.

Item settings versus SKU settings

Business Central supports planning parameters at both the Item and SKU level. SKUs allow different replenishment settings for specific combinations of item, location, and variant.

The Enhanced Planning Worksheet’s Purchase Plan operates on Stockkeeping Units, so the planning settings applicable to the SKU are especially important when planning inventory independently by location.

Microsoft provides additional information about how Item and SKU planning settings are used in About planning functionality.

Choosing a reordering policy

As a general guide:

Reordering Policy	Typical purpose	Calculate Purchase Plan
Fixed Reorder Qty.	Maintain stock using consistent replenishment quantities	Reorders when the reorder level is reached and uses the configured Reorder Quantity
Maximum Qty.	Maintain inventory up to a target maximum	Replenishes toward Maximum Inventory
Lot-for-Lot	Replenish according to demand	Covers the calculated net shortage, including Safety Stock
Order	Replenish specific demand	Covers the calculated net shortage, including Safety Stock

The appropriate policy depends on how the item is purchased and stocked. Microsoft provides additional guidance in Setup best practices: Reordering policies.

Related documentation

• Enhanced Planning Worksheet
• Enhanced Planning Worksheet Setup
• Microsoft: Design details – Handling reordering policies
• Microsoft: Design details – Planning parameters
• Microsoft: About planning functionality
• Microsoft: Setup best practices – Reordering policies