A low IPI score is costing you storage. Here's how to fix it

Running a successful Amazon FBA business means juggling a lot of moving parts—pricing, listings, advertising, and fulfillment. But one metric quietly shapes how much storage space you have access to, and how much you'll pay if things go wrong: your Amazon IPI score. 

If you've noticed your storage limits shrinking or received warnings about your inventory performance, your IPI score is likely the culprit. The good news? Once you understand how it works, improving it is very much within your control. This guide breaks down everything you need to know about the Amazon Inventory Performance Index—what it measures, why it matters, and the specific steps you can take to raise your score and protect your FBA business. 

What is the IPI score on Amazon? 

The Inventory Performance Index (IPI) is a score Amazon uses to measure how efficiently you manage your FBA inventory. Think of it as a report card for your inventory health. Amazon uses it to determine how much warehouse space you're eligible to use in their fulfillment centers. 

Your IPI score ranges from 0 to 1,000. Amazon considers a score of 450 or above to be healthy. Fall below that threshold, and you could face storage limits that restrict how many units you can send to Amazon's fulfillment centers. 

You can find your current IPI score in Seller Central under Inventory > Inventory Performance Dashboard. Amazon updates this score weekly, so changes you make now will begin to reflect in your score relatively quickly. 

Why your IPI score matters for FBA sellers 

Amazon's fulfillment network is enormous, but warehouse space isn't unlimited. To keep things running efficiently, Amazon rewards sellers who manage inventory well with more storage capacity—and penalizes those who don't. 

A low IPI score can trigger several consequences: 

• Reduced storage limits: Amazon will cap how many units you can store across all inventory types (standard-size, oversize, apparel, footwear). 

• Overage fees: If your inventory exceeds your assigned storage limit, Amazon charges overage fees on a per-cubic-foot basis. 

• Disrupted restocking: With limited storage, you may not be able to send in enough units to meet customer demand, leading to stockouts and lost sales.
  

For high-volume sellers or those approaching peak seasons, these restrictions can be seriously damaging. A healthy IPI score, on the other hand, gives you more flexibility and removes those storage barriers entirely. 

How Amazon calculates your IPI score 

Amazon hasn't published the exact formula, but it has confirmed that your IPI score is influenced by four key performance factors. Understanding each one is the first step toward improving your score. 

Excess inventory percentage 

This measures how much of your inventory Amazon considers to be overstocked. Specifically, it flags units that have more than 90 days of supply on hand relative to your sales velocity. Too much excess inventory ties up space and signals poor planning. 

Sell-through rate 

Your sell-through rate reflects how quickly you're selling through your inventory compared to how much you're storing. It's calculated as the ratio of units sold and shipped over the past 90 days to the average number of units on hand during that period. A higher sell-through rate tells Amazon your inventory moves efficiently. 

Stranded inventory percentage 

Stranded inventory refers to units sitting in Amazon's fulfillment centers that don't have an active listing. This can happen when a listing is suppressed, deleted, or violates a policy. Amazon can't sell what isn't listed—so stranded inventory is essentially dead weight. 

In-stock rate 

This tracks whether you're staying in stock on your best-selling products. Running out of stock on high-demand ASINs hurts both your sales and your IPI score, since it signals unreliable inventory management. 

How to improve your inventory performance index 

With those four factors in mind, here are the most effective strategies for raising your score. 

Clear out excess inventory. 

Start by reviewing your Inventory Performance Dashboard and identifying products flagged as excess. For these items, consider: 

• Running a promotion or lightning deal to accelerate sales 

• Lowering your price temporarily to move units faster 

• Using Amazon's FBA Liquidations or FBA Donations programs to remove inventory you don't expect to sell 

• Creating a removal order to pull slow-moving stock back to your warehouse 
  

Reducing excess inventory not only improves your score—it also reduces your monthly storage fees. 

Improve your sell-through rate. 

A strong sell-through rate comes down to keeping the right amount of stock at all times. To boost yours: 

• Use Amazon's restock recommendations to guide how much you send in and when 

• Tighten your replenishment cycles so you're sending smaller, more frequent shipments rather than large infrequent ones. 

• Run deals on slower-moving products to increase velocity. 
  

If a product consistently has a poor sell-through rate, it may be worth reconsidering whether FBA is the right fulfillment method for it. 

Fix stranded inventory fast. 

Stranded inventory is one of the easiest IPI problems to resolve. In Seller Central, navigate to Inventory > Fix Stranded Inventory, and you'll see a list of all affected ASINs along with the reason each listing is inactive. 

Common causes include: 

• Listing policy violations that need to be resolved 

• Listings that were accidentally deleted or closed 

• Pricing errors that triggered automatic suppression 
  

Many of these can be fixed in just a few clicks. Set a reminder to check this page weekly—it's a quick win that adds up over time. 

Maintain stock on top-performing products. 

Stockouts on popular ASINs hurt both your sales rank and your IPI score. To stay ahead: 

• Set reorder alerts based on your average daily sales and lead times. 

• Build in a safety stock buffer for your best sellers, especially heading into Q4 or promotional periods. 

• Monitor your days of supply metric in the Inventory Performance Dashboard to spot potential stockouts early. 
  

The goal isn't to overstock—it's to stay in stock without accumulating excess inventory. Finding that balance is the heart of good FBA inventory management. 

Use the IPI score calculator and dashboard tools. 

Amazon provides built-in tools to help you model how changes will affect your score. The Inventory Performance Dashboard shows you a projected impact for actions like creating removal orders or improving sell-through. Use these projections to prioritize which changes will move the needle most. 

Third-party inventory management tools like Inventory Planner, RestockPro, and Skubana can also help you manage FBA restock limits more precisely and automate much of the replenishment process. 

How long does it take to improve your IPI score? 

Amazon recalculates your IPI score weekly, so meaningful improvements can show up relatively quickly—especially if you address stranded inventory or remove a large volume of excess stock. That said, some factors like sell-through rate reflect a 90-day window, so sustained effort over several weeks is needed to see a significant lift. 

If you're close to the 450 threshold, prioritize the highest-impact changes first: fix stranded listings, remove or liquidate flagged excess inventory, and ensure your top sellers are fully in stock. 

Frequently asked questions 

What is a good IPI score on Amazon? Amazon considers an IPI score of 450 or above to be in good standing. Sellers with scores above this threshold are not subject to storage restrictions. The closer your score is to 1,000, the more efficiently Amazon views your inventory management. 

What happens if my IPI score drops below 450? If your IPI score falls below 450, Amazon will assign you storage limits for each inventory type. If your current inventory exceeds those limits, you'll be charged overage fees until your levels come down. 

Does Amazon update IPI scores in real time? No. Amazon updates IPI scores on a weekly basis. This means you won't see the impact of changes you make instantly, but you should begin to see movement within one to two weeks. 

Can I have multiple IPI scores? You have one IPI score per Seller Central account. However, the score reflects performance across all your FBA inventory, so improving any of the four contributing factors will benefit your overall score. 

What is the difference between IPI and the sell-through rate? Sell-through rate is one of the four metrics that contribute to your overall IPI score. Your IPI score is a composite measure of inventory efficiency, while sell-through rate specifically looks at how quickly you're selling through your stored inventory relative to what's on hand. 

Take control of your IPI score before it takes control of your business. 

Your Amazon IPI score is more than a number—it's a direct line to your storage capacity, your selling flexibility, and ultimately your bottom line. Sellers who monitor it consistently and act on the underlying data are the ones who avoid costly storage penalties and maintain the space they need to grow. 

Start by pulling up your Inventory Performance Dashboard today. Identify where your score is being dragged down, prioritize the quick wins, and build inventory management habits that keep your score above 450 for the long term. With a little consistency, your IPI score will reflect exactly what you've built: a well-run, efficient FBA operation.