The Business Central reservation engine
How reservations work in Business Central — automatic vs manual, item tracking, order-to-order binding, and the trade-offs.
The reservation engine in Business Central links a piece of supply (inventory on hand, an inbound purchase order, a production order, a transfer order) to a specific demand (a sales order line, a production component, a service order). Reservations are how the system promises one customer that this particular stock will be reserved for their order rather than the next person who logs in.
Why reserve at all. Without reservations, a sales order line just expresses demand against a pool — and that pool is up for grabs by anyone else who picks faster. Reserving converts the promise into a binding allocation that survives until the order is shipped or the reservation is cancelled.
Automatic, optional, never. Each item has a Reserve field with three settings: Never (no reservations allowed), Optional (users reserve manually when needed, the default), and Always (every demand line is reserved as it's created, blocking creation if no supply exists). Most companies use Optional and reserve selectively.
Manual reservations. From a sales order line, users open the Reservation Entries page and pick which supply to bind to: on-hand quantity, an inbound purchase, a production order, an assembly order, a transfer order. The reservation entry stores the link. Posting the source consumes the reservation.
Order-to-order binding. A stronger form of reservation, used for make-to-order and configure-to-order, where the supply is created specifically for the demand. The link is bidirectional — if the sales order quantity changes, the production order changes; if the production order is cancelled, the demand becomes unreserved. Order-to-order is the operating model for many engineer-to-order shops.
Item tracking and reservations. When items have lot or serial numbers, reservations can be at the tracking level (this serial number, this lot) or at the quantity level. Specific tracking reservations are common in pharma, food, and high-value goods.
Reservations and planning. Reserved supply is visible to MRP and is excluded from the available-to-promise pool. The planning worksheet honours reservations and won't suggest cancelling a reserved supply order.
Trade-offs. Heavy reservation discipline gives reliable delivery promises but increases administrative load. Many companies start with Optional and reserve only for committed orders above a value or with delivery commitments.
Related guides
- Assembly orders in Business CentralHow Business Central handles assembly orders — assembly BOMs, assemble-to-order vs assemble-to-stock, and when to use assembly vs production orders.
- Inventory and warehouse management in Business CentralHow Business Central tracks items, locations, lots, serials, and warehouse operations — from basic stock to directed put-away and pick.
- Inventory costing methods in Business Central, comparedFIFO, LIFO, Average, Standard, and Specific — what each costing method means, and how to choose the right one in Business Central.
- Item attributes and variants in Business CentralHow Business Central handles product variations — variants for stock-keeping, attributes for searching, and where the model fits and where it doesn't.
- Item categories in Business CentralHow to structure a Business Central catalogue with item categories — hierarchy, defaults, attributes, and the integration with templates and reporting.