Stockout cost is the economic impact of demand that cannot be fulfilled when needed. It may include lost contribution, rush freight, a more expensive substitute, disruption and an uncertain effect on future customer behavior. Calculate the outcomes separately so the same sale is not counted as both lost and successfully substituted.
Compare mutually exclusive outcomes
An illustrative restaurant expected to sell 14 portions with $19 contribution per portion before other costs. If all 14 sales are lost, the immediate lost contribution is:
14 × $19 = $266
If an acceptable substitute preserves all 14 sales but costs $3 more per portion, the incremental cost is instead:
14 × $3 = $42
Do not add $266 of lost contribution to $42 of substitution cost for those same preserved sales. For a mixed outcome, count the lost and retained portions separately. Clinical, food-safety and other product-approval decisions remain with the appropriate professional or responsible operator.
Estimate longer-term effects as scenarios
A future customer loss is not directly observed from one unavailable item. If there is evidence for a changed retention rate, apply it to expected future contribution, over a stated horizon, and show the uncertainty. Annual customer revenue is not automatically lifetime value or profit.
Do not add a future-value estimate that already includes the current lost sale. Present low, central and high scenarios when the probabilities are uncertain, and keep observed rush costs separate from modeled future effects.
Compare the buffer that would actually help
Extra inventory has acquisition, holding and possible loss costs. It only avoids a shortage if the right quantity is usable at the required location and time.
For example, five extra units costing $9 each, with an assumed 35% annual holding rate, incur 5 × $9 × 0.35 / 365 = $0.043 per day of modeled holding cost, about four cents. They cannot cover a 14-unit shortage by themselves. Product expiry and the cash needed to buy them require separate review.
A safety-stock model helps compare policies under assumptions; it does not guarantee that a particular stockout will be prevented.
Use the order history to identify avoidable losses
LineNow's purchase-order tracking connects supplier confirmations, delays, partial shipments and receiving. Use that history to identify whether an unavailable item came from a late order, a delayed supplier, an inaccurate stock count or an unapproved substitution.
Revenue-at-risk estimates are planning signals, not measured lost profit. Confirm the metric's assumptions before using it to justify extra stock or a supplier change.