How This Calculator Works
This calculator adds up what stockouts cost across your catalog in one quarter. Every figure comes from a number you enter. It does not fill in any gaps for you.
1. Direct Lost Revenue
These are the sales you would have made if the product had been in stock. We take the SKUs that ran out, times the days each was out, times the units each sells a day, times your price. Use the rate a SKU sells at when it is in stock. Its average over the whole quarter is lower, because the days at zero pull it down.
2. Ranking Impact (your estimate)
On Amazon, a listing that runs out can lose its place in search. When you restock, sales can stay below normal for a while as it climbs back. How much depends on your category and your listing, so we do not guess. If you have seen it in your own sales, enter it as a share of the direct loss. Leave it at 0 to count none.
3. Emergency Restock Premium (your estimate)
Running out can push you into air freight, rush runs, or faster shipping. If you paid for those, enter the extra cost as a share of the direct loss. Leave it at 0 if you did not.
The Yearly Figure
The yearly line is your quarter times four. It is only as good as your quarter is typical. If you sell more in one season, run the calculator once for each quarter and add them up.
Where to Find Your Numbers
- Active SKUs: the products you sell that are live today.
- Share that ran out: count the SKUs that hit zero at least once last quarter, then divide by your active SKUs.
- Days out: for those SKUs, the average number of days each sat at zero in the quarter.
- Units a day: what a SKU sold on the days it was in stock, divided by those days.
What This Estimate Does Not Include
The calculator counts only what you enter. It leaves out:
- Repeat buyers who switch to a rival for good
- Ad spend on listings you could not fill
- Harm to your brand from "Currently Unavailable" badges
- Staff time spent on fire drills
Reducing Your Stockout Cost
The most effective way to reduce stockout costs is to prevent them:
- Demand forecasting that tells you what to reorder before you run out
- Safety stock buffers sized to your actual variability
- Reorder point alerts that fire at the right time, not too early or too late