Stockouts

A stockout occurs when available inventory cannot satisfy demand for a specified item at a specified location and time. Physical stock and stock available to promise can differ: units may be damaged, reserved, or recorded in another location.

In a hypothetical store, a customer requests ten units and six are available for immediate supply. Four units are unmet at that point. This does not mean four customers were lost. The customer may accept partial delivery, wait, substitute another product, or cancel.

Record the item, location, requested quantity, availability rule, and eventual outcome. Sales observed while stock is unavailable may understate demand, because some customers never place an order. Forecast errors, delayed supply, allocation rules, and inaccurate records are possible causes to investigate; the stockout alone does not identify which one occurred.

Related reference: Shopify inventory reporting documentation. Examples and calculations here are illustrative.