Why an Amazon Stockout Costs More Than the Sales You Missed

The obvious cost, and the one that lingers

The visible cost of running out of stock is simple: no inventory means no sales during the gap. The less obvious cost is that a stockout can also ding your listing's search ranking and your account's Inventory Performance Index (IPI) — and unlike the lost sales, which stop the moment stock arrives, both of those effects can take real time to recover even after you're back in stock.

The formula that keeps you ahead of it

A reorder point answers one question precisely: at what inventory level do I need to place a new order so the replacement stock lands before I run out? Reorder Point = (Average Daily Sales × Lead Time in Days) + Safety Stock. The first term covers ordinary expected demand during the wait for a new shipment; the safety stock on top covers the unexpected — a sales spike, a supplier delay, a shipping hiccup.

Lead time means the whole wait, not just shipping

A common miscalculation is measuring lead time as only the supplier's manufacturing or shipping time, leaving out your own prep work, freight-forwarder handling, and the time for stock to actually check into an Amazon warehouse. All of that belongs in the lead-time number, since it's all time your shelf sits empty if you order too late.

Know your number before you're guessing

Our Inventory Reorder Point Calculator turns your sales rate, lead time and safety buffer into an exact reorder point, plus roughly how many days you have left at your current inventory level — so restocking is a scheduled decision, not a scramble.