Glossary

IPI (Inventory Performance Index)

Last updated: March 17, 2026

IPI defined: The Inventory Performance Index

The IPI (Inventory Performance Index) is a metric calculated by Amazon that measures how efficiently you manage your FBA inventory. The IPI score ranges from 0 to 1,000 – the higher, the better.

Amazon uses the Inventory Performance Index to optimize storage space in its fulfillment centers. Sellers with a high Amazon IPI receive more storage capacity, while sellers with a low IPI can be restricted. The score is updated weekly and is based on your performance over the last 90 days.

The four main factors of the IPI

Amazon calculates the IPI from four main factors. The exact weighting is not public, but all four areas matter:

1. Excess Inventory

Products that have been sitting in the warehouse for more than 90 days and whose stock exceeds the forecasted sales. Excess inventory blocks storage space and incurs fees.

2. Sell-Through Rate

The ratio of units sold to inventory stored over the last 90 days. A high sell-through rate shows that your inventory rotates efficiently.

3. Stranded Inventory

Products that are in the FBA warehouse but cannot be sold – for example, because the listing has been deactivated. Stranded inventory should be resolved as quickly as possible.

4. In-Stock Rate

The percentage of time your in-demand products were available. Out-of-stock situations hurt not only revenue but also your IPI.

IPI threshold and consequences

Amazon has set a minimum threshold for the IPI. If your score falls below this value, restrictions can follow:

Current IPI threshold: 400

The threshold was lowered from 450 to 400. However, Amazon can adjust this value at any time.

Consequences when the IPI drops below 400:

Storage limit: Amazon restricts the amount of inventory you can send in
Storage Utilization Surcharge: Additional fees of up to $10 per cubic foot for excess inventory
No new shipments: In extreme cases, Amazon can refuse to accept new shipments

Newer fee structure (since 2025):

The Storage Utilization Surcharge kicks in at more than 26 weeks of inventory on hand
Long-term storage fees begin after just 271 days (instead of 365)
Monthly inventory fees are tiered by product size

Improving your IPI: Practical strategies

A good IPI requires proactive inventory management. Here are proven strategies:

Reduce excess inventory

Use discount promotions, Lightning Deals, or coupons to sell off slow-moving products. For extremely slow products: removal order or liquidation.

Fix stranded inventory

Regularly check the “Fix Stranded Inventory” section in Seller Central. Reactivate listings or remove products you no longer need.

Optimize reordering

Use Amazon's restock recommendations and plan replenishments in good time to avoid going out of stock without overordering.

Use external storage

Keep part of your stock in an external warehouse (3PL) and send only what you need to Amazon. This keeps you flexible and avoids excess inventory.

Use AWD

Amazon Warehousing & Distribution (AWD) enables bulk storage outside of FBA without that inventory affecting your IPI.

Monitoring your IPI: Where do I find my score?

You can find your current IPI score in Seller Central:

1. Sign in to Seller Central
2. Go to “Inventory” → “Inventory Planning”
3. Click on “Inventory Performance” or “Dashboard”
4. Your IPI score is displayed prominently at the top

In the dashboard you also see detailed breakdowns for each of the four factors, recommendations from Amazon, and historical data on how your IPI has developed.

Frequently asked questions (FAQ)

How often is the IPI updated?

The IPI is updated weekly. Amazon evaluates your inventory based on the data from the last 90 days. Improvements therefore don't take effect immediately but show up over several weeks.

Does FBM inventory affect my IPI?

No, the IPI only applies to FBA inventory. Products you ship via FBM (Fulfillment by Merchant) are not taken into account. Switching to FBM can therefore be one strategy for improving your IPI.

What is a good IPI score?

An IPI above 400 is the minimum to avoid restrictions. A score of 500–600 is good, 700+ is excellent. The best sellers reach values around 800–900, which points to very efficient inventory management.

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