How to Interpret Your Results
The calculator breaks each stockout incident into three costs. Most sellers only think about the first one.
Direct Lost Revenue
The straightforward math: price × daily units × days out of stock. If you sell a $30 product at 3 units per day and you're out for a week, that's $630 in direct sales you'll never recover.
Amazon Ranking Impact (35%)
When an Amazon listing goes out of stock, its organic rank drops, sometimes within 24 hours. When inventory returns, you don't snap back to where you were. The recovery period can take 1-3 weeks, during which your conversion rate and keyword positions run below your pre-stockout baseline. Research suggests this costs an additional 30-40% on top of the direct loss. We use 35% as a conservative midpoint.
Emergency Restock Premium (15%)
Stockouts force reactive decisions: air freight instead of ocean, rush production runs, expedited last-mile. These premiums typically add 10-20% to what you would have paid if you'd ordered on schedule. We use 15%.
Annual Projection
The annual figure assumes 6 incidents per year, roughly one every 8 weeks for a single SKU. Most sellers with 50+ active SKUs experience far more than 6 total incidents across their catalog. Multiply the per-incident total by your realistic annual incident count for a more accurate picture.
What This Calculator Does Not Include
The estimate is deliberately conservative. It excludes:
- Customer lifetime value lost when a buyer switches to a competitor
- Advertising spend wasted on out-of-stock listings (PPC still charges clicks)
- Inventory holding cost for the excess safety stock you'll need to add
- Staff time spent on fire drills, supplier calls, and expedited orders
How to Reduce Your Stockout Cost
The most reliable fix is earlier reorder triggers with accurate demand signals:
- Calculate your reorder point: the inventory level at which you need to place an order to avoid running out during lead time.
- Size your safety stock buffer: the cushion you need to absorb demand spikes and supplier delays.
- Use demand forecasting to move from reactive reorders to scheduled, data-driven replenishment.
ReplenishRadar runs these calculations automatically across your full catalog, using real sales velocity and supplier lead times from your connected stores.