Overview

Amazon's Inventory Performance Index (IPI) is a metric that measures how efficiently sellers manage their FBA inventory. The score plays a direct role in determining storage capacity limits and can affect a seller's ability to send new inventory to Amazon's fulfillment centers. Understanding how the IPI works is essential for any FBA seller looking to maintain healthy inventory levels and avoid costly storage restrictions.

Key Points / What Sellers Need to Know

• IPI scores range from 0 to 1,000 — Higher scores indicate better inventory management, while lower scores suggest excess or stranded inventory that needs attention.
• Minimum threshold applies — Amazon sets an IPI threshold (historically around 400-450) that sellers must meet to avoid storage volume limits on their accounts.
• Scores are evaluated quarterly — Amazon checks IPI scores at set intervals, typically at the end of each quarter, to determine whether storage limits will apply for the following quarter.
• Only Professional sellers see IPI — The IPI score and associated dashboard are available exclusively to sellers enrolled in a Professional selling plan.
• Multiple factors drive the score — Excess inventory, sell-through rate, stranded inventory, and in-stock rate on popular items all contribute to the final IPI number.

How the IPI Score Is Calculated

Amazon calculates the IPI based on several inventory health factors weighted together into a single composite score. The primary components include your excess inventory percentage, which measures units that have been in fulfillment centers longer than expected based on demand forecasts. Your FBA sell-through rate looks at how quickly your inventory moves relative to how much you keep on hand. Stranded inventory — listings that are inactive but still have units stored at Amazon — also drags the score down. Finally, your FBA in-stock rate on replenishable items rewards sellers who keep their best-selling products available without running out. Amazon does not publish the exact formula or weighting of each factor, but addressing problems in any of these areas will generally improve your score.