IPI (Inventory Performance Index) is Amazon's score, from 0 to 1000, for how efficiently an FBA seller manages inventory. It is shown on the Inventory Performance dashboard in Seller Central and updated weekly. Amazon calculates it from four factors: excess inventory, FBA sell-through rate over the trailing 90 days, stranded inventory, and in-stock rate on replenishable products. Amazon sets a threshold score and reviews accounts against it periodically; sellers below the threshold can have their FBA storage capacity restricted.
Why it matters
IPI is the number that decides how much you are allowed to send to Amazon. Fall below the threshold at a review date and your storage limits for the coming period shrink, which can mean being unable to stock up before Prime Day or Q4 regardless of demand. Because the score is built from the trailing quarter, a bad IPI is slow to fix, so it has to be managed before a peak, not during one.
The four factors also happen to be the same things that hurt profit. Excess stock pays storage fees, stranded stock pays fees and sells nothing, and stock-outs on replenishable items lose sales and rank. Working on IPI is usually working on margin.
What moves it
- Excess inventory, defined by Amazon as units beyond roughly 90 days of cover, weighted by the storage they occupy.
- Sell-through rate, units sold divided by average units on hand over 90 days.
- Stranded inventory, as a share of total.
- In-stock rate on products Amazon considers replenishable.
- Time. All four are trailing measures, so changes show weeks later.
How we use it
IPI sits in the stock and cash check we run before any scaling decision. If a client is near the threshold, the plan pairs the sales push with a clean-up: removal orders or promotions for excess SKUs, relisting stranded units, and restock timing that keeps replenishable items in stock. The score and the next review date appear in the monthly report for FBA-heavy accounts.