Amazon IPI Score: What It Is and How to Improve It

The Inventory Performance Index (IPI) is a 0-1000 score that measures how efficiently you manage your FBA inventory. Amazon uses your IPI score to determine how much storage space you can use in fulfillment centers. A low IPI can result in storage limits that restrict your ability to send new inventory.

The threshold

Amazon sets the IPI threshold quarterly. As of 2024, the threshold is 400. Scores below 400 trigger storage limitations. Scores above 400 give you unlimited (practically speaking) storage space.

What affects IPI

Excess inventory: Holding more inventory than you can sell in 90 days increases your excess inventory rate. This is the biggest driver of low IPI scores. If you have 500 units of a product that sells 50/month, you have 9 months of supply — that is excess inventory.

Stranded inventory: Inventory in a fulfillment center with no active listing attached. Amazon cannot sell it but you pay for it. Find and fix stranded inventory weekly.

In-stock rate: Are your products in stock when customers want to buy them? Products that go out of stock frequently drag down your IPI. Keep your most important ASINs at 30+ days of supply.

Sell-through rate: Units sold in the past 90 days divided by average units on hand. A higher sell-through rate improves IPI. Slow-moving inventory drags it down.

Raising a low IPI score

Create removal orders for excess inventory. Send products with more than 90 days of supply back to yourself or to a 3PL. The cost of removal is usually lower than the ongoing storage fees for excess units.

Fix stranded inventory. Go to Fix Stranded Inventory and either relist or remove every stranded ASIN.

Run promotions on slow-moving products to improve sell-through rate. Even if margins are thin, moving inventory improves IPI and avoids long-term storage fees.

Monitoring IPI

Check your IPI score in Seller Central > Inventory > Inventory Performance. Amazon updates the score weekly. You can see the breakdown of each contributing factor and which ASINs are dragging your score down most.

Amazon sends email warnings when IPI drops toward the threshold before storage limits are applied. Do not ignore these warnings — act on them immediately.