IPIInventory Performance Index
IPI is Amazon's score (0–1000) measuring how efficiently an FBA seller manages their inventory. A low IPI score triggers storage restrictions and surcharges.
What is IPI?
Amazon's Inventory Performance Index measures four factors: excess inventory percentage, sell-through rate, stranded inventory percentage, and in-stock rate. Each factor is weighted in Amazon's proprietary formula, but sell-through rate and excess inventory tend to have the most impact. Amazon updates the IPI score weekly.
Sellers with an IPI below Amazon's threshold (currently 400) face storage capacity limits — Amazon restricts how much inventory they can send to FBA warehouses. This can be devastating during Q4 when restocking capacity is most critical. Sellers with IPI above 450 face no capacity restrictions and are eligible for preferred storage rates.
IPI is a rolling average, not a point-in-time metric. A single bad month of excess inventory or stockouts doesn't immediately tank the score — but sustained poor inventory management will gradually erode it.
Why it matters for sellers
A low IPI score at the wrong time — such as September when sellers are building Q4 inventory — can prevent you from sending enough stock to FBA for peak season. This directly caps your revenue during the most valuable selling period of the year. Sellers have lost tens of thousands in peak-season sales because IPI restrictions prevented adequate restocking.
How to use IPI
Check your IPI score weekly in Seller Central (Inventory > Inventory Planning). Focus on the biggest IPI killers: excess inventory (units with 90+ days of supply) and low sell-through rate. For excess inventory, run promotions or create removal orders before the 365-day long-term storage fee kicks in.
For each SKU, target 45–90 days of cover at FBA. Under 30 days risks stockouts; over 90 days increases excess inventory flag risk. Use Amazon's restock recommendations as a baseline, then adjust based on your lead times and supplier reliability.
Real-world example
A seller with an IPI of 380 faces Q4 storage restrictions — they can only send 2,000 units when they need 8,000 for peak season. They run aggressive promotions on slow-moving ASINs in September, clear excess inventory, and raise IPI to 440 by October — unlocking full capacity for their Q4 restock. Revenue that Q4 is 2.3× the previous year's.
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Frequently asked questions about IPI
What is a good IPI score on Amazon?
450+ is considered good — sellers above this threshold have no storage restrictions. The target is 500+ for healthy inventory management. Amazon's minimum threshold for unrestricted storage is 400 — below this, restrictions apply.
How do I improve my IPI score quickly?
The fastest improvements come from: removing or liquidating excess inventory (items with 90+ days of cover), fixing stranded inventory (listings with stock but no active offer), and ensuring your top-selling ASINs stay in stock. These three actions address the four IPI factors simultaneously.
Does IPI affect my ability to create new FBA shipments?
Yes. If your IPI drops below Amazon's threshold, Amazon may restrict your storage limits for each product type (standard-size, oversize, apparel, footwear). You can still create FBA shipments but may be limited in the quantity you can send per restock period.