How to Interpret Your Results
The calculator breaks each stockout incident into three costs. The first comes from your own sales numbers. The other two are your estimates. They start at 0%, so they add nothing until you fill them in.
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.
Ranking Impact (your estimate)
When an Amazon listing goes out of stock, its rank in search can drop. When stock comes back, it can take time to climb back, and sales run lower while it does. How much you lose depends on your product, your rank, and how long you were out, so the calculator leaves it to you. Enter it as a share of the direct loss. If you have not seen it in your own sales, leave it at 0%.
Emergency Restock Premium (your estimate)
Running out can force rushed choices: air freight instead of ocean, rush production runs, faster shipping to the warehouse. If you have paid for these, enter the extra cost as a share of the direct loss. If you restock on your normal schedule, leave it at 0%.
Annual Projection
The annual figure is the cost per incident times your stockout incidents a year. It starts at 1. Each incident is one SKU running out once, so if several SKUs run out, count each one.
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.