FBA IPI Score – What Drops It and How to Fix It

The notification appears in Seller Central with no warning. Your FBA storage capacity has been limited due to your Inventory Performance Index score. You are blocked from sending new shipments to Amazon fulfillment centers. Q4 is eight weeks away.

The Inventory Performance Index is a 0 to 1000 score Amazon assigns every FBA seller based on how efficiently they manage inventory in Amazon fulfillment centers. Drop below 400 and Amazon restricts how much cubic footage you can hold across all of FBA. The restriction is enforced at the shipment creation level. You cannot create inbound shipments that exceed your storage limit regardless of what products you sell or how long you have been selling.

Recovery from a low IPI score typically takes 6 to 10 weeks from a 350 starting point. For sellers who discover the problem in late September the math does not work for Q4. This guide explains what the four score components are, which ones carry the most weight, what the score actually costs when it drops below 400, and the specific actions that move the score fastest.

The Four IPI Components

Amazon does not publish the exact formula or the weighting of each component. It surfaces four metrics clearly in Seller Central under Inventory Performance and states these are the basis of the score. Based on consistent seller community observation and data, the first two components carry significantly more weight than the last two.

Component 1: Excess Inventory Percentage (highest weight)

This measures the percentage of your FBA inventory units that Amazon considers overstocked based on your recent sales velocity. Amazon flags units as excess when you have more than 90 days of supply on hand based on trailing 90-day sales. Excess inventory is the single biggest driver of low IPI scores because it represents exactly what Amazon is trying to prevent: sellers using FBA warehouses as long-term storage.

A catalog where 40 percent of units are flagged as excess generates a meaningfully lower IPI than a catalog where excess inventory is under 10 percent. The fix is reducing days of supply on slow-moving SKUs through price reductions, removal, or liquidation.

The target: keep excess inventory percentage below 10 percent across your catalog. The practical metric to watch is Days of Inventory (DOI). A DOI target of 30 to 45 days across your active catalog keeps most sellers out of the excess inventory flag zone.

Component 2: Sell-Through Rate (high weight)

Sell-through rate measures the percentage of your total FBA inventory (including on-hand plus in-transit) sold and shipped over the trailing 90 days. A high sell-through rate signals healthy inventory velocity. A low sell-through rate signals dead stock accumulating in fulfillment centers.

Amazon considers a sell-through rate of above 2.0 healthy for most categories. Below 1.0 begins pulling the IPI score down. Products that have been in FBA for 60 or more days without meaningful sales velocity are the primary driver of low sell-through rates.

The fix for low sell-through rate is identical to the fix for excess inventory: reduce price to accelerate units, run a removal order on dead SKUs, or use Amazon’s liquidation program for units that will not sell at any reasonable price.

Component 3: Stranded Inventory Percentage (moderate weight)

Stranded inventory is inventory physically present in Amazon fulfillment centers but not actively listed for sale because of a listing error, suppressed listing, or account policy issue. A product with a suppressed listing cannot be purchased. Amazon cannot fulfill it. The inventory occupies warehouse space and generates storage fees while generating zero revenue.

Stranded inventory appears in Seller Central under Inventory, Fix Stranded Inventory. The fix is typically quick: resolving the listing error, reactivating a suppressed listing, or creating a new listing for orphaned inventory. Amazon confirms stranded inventory can be resolved within 48 hours for most listing errors.

The target: keep stranded inventory at zero. Any stranded inventory is avoidable and should be resolved immediately upon appearance. A weekly check of the Fix Stranded Inventory report prevents chronic stranded inventory from dragging the score.

Component 4: In-Stock Rate (lower weight)

In-stock rate measures the percentage of time your products have been in stock over the past 30 days weighted by the number of units that would have sold if the item had been in stock. Running out of stock reduces the in-stock rate and pulls the IPI score down.

The irony is that running out of stock also triggers the low-inventory fee which charges $0.32 to $2.09 per unit when days of supply drops below 28 days. A seller who reduces IPI by holding less inventory risks triggering the low-inventory fee on the same products.

The sweet spot in 2026: maintain 30 to 45 days of supply per FNSKU. Enough to keep in-stock rate healthy and avoid the low-inventory fee. Not so much that excess inventory percentage flags accumulate. For the complete reorder point formula that keeps inventory in this window see FBA Reorder Point Formula.

What a Low IPI Score Actually Costs

Below 400 the consequences are operational not just cosmetic.

Storage capacity restriction:
Amazon assigns a monthly cubic foot limit to your FBA account based on your IPI score, sales velocity, and inventory efficiency. Below 400 this limit is meaningfully reduced from the default allocation. You cannot create inbound shipments that exceed the limit.

The practical impact depends on your catalog size and velocity. A seller with 100 SKUs and stable velocity may find the restricted limit is workable. A seller preparing Q4 inventory build may find the limit prevents sending 60 percent of the inventory needed to cover seasonal demand.

Overage charges:
If your existing inventory exceeds the storage limit imposed by a low IPI score Amazon charges a per-cubic-foot overage fee on the excess. This fee compounds on any inventory already in fulfillment centers above the new limit.

ASIN-level restock limits:
Since mid-2025 Amazon has reactivated ASIN-level quantity restrictions alongside account-wide capacity limits for sellers below the IPI threshold. Individual SKUs can be capped at specific restock quantities independent of the account-wide cubic foot limit. High-velocity sellers can find their bestselling ASIN restricted to a quantity that causes stockouts even when account-wide storage capacity remains.

The Q4 timing problem:
Amazon evaluates your IPI score during the last six weeks of each quarter to determine storage limits for the following quarter. A seller with a low IPI entering Q3 (July through September) will have restricted Q4 capacity regardless of any improvements made after the evaluation window closes. This is why discovering a low IPI score in October is often too late to fix Q4 capacity constraints.

For the complete guide on FBA storage fees including the aged inventory surcharge schedule and when removal is cheaper than continued storage see FBA Long-Term Storage Fees.

The Fix Priority Order

Not all four components respond at the same speed. The recovery plan should address them in the order that produces the fastest score improvement.

Week 1 to 2: Fix stranded inventory completely.
Stranded inventory is the fastest fix. Check Fix Stranded Inventory in Seller Central and resolve every listing error. This component can move from elevated to zero within 48 to 72 hours of resolving listing issues. Every unit of stranded inventory eliminated improves this component immediately.

Week 1 to 4: Reduce excess inventory on slow-moving SKUs.
This is the highest-weight component and requires the most work. Pull the Inventory Age report in Seller Central. Identify every ASIN with 90 or more days of supply. For each flagged ASIN choose one action:

Price reduction: drop price to move units faster. Even a 15 to 20 percent reduction on a slow-mover accelerates sell-through and reduces excess inventory percentage simultaneously improving both the excess inventory and sell-through rate components.

Removal order: remove units from FBA and return them to your own storage or sell through other channels. Removal fee is typically $0.97 to $1.26 per unit depending on size tier. For products where continued FBA storage generates aged inventory surcharges removal is cost-effective.

Liquidation: submit units to Amazon’s Liquidations program at a recovery rate of approximately 5 to 10 percent of the average selling price. Use this as a last resort for products where removal cost exceeds recovery value through other channels.

Week 2 to 6: Optimize replenishment to maintain in-stock rate without overstocking.
Once excess inventory is reduced focus on right-sizing replenishment quantities. The target is 30 to 45 days of supply per FNSKU. This keeps in-stock rate healthy and avoid the low-inventory fee.

Use the FBA Fee Calculator to model storage costs at different inventory levels so you can identify the point where holding excess inventory costs more than the revenue lost from a stockout on slow-moving SKUs.

Week 4 to 10: Wait for the rolling window to catch up.
IPI scores reflect rolling 90-day performance. Even after making all the right operational changes the score takes 4 to 10 weeks to fully reflect the improvements. There is no way to accelerate this beyond making the changes as early as possible. Recovery from 350 to above 400 typically takes 6 to 10 weeks from the start of focused remediation.

Maintaining IPI Above 550 Long Term

The minimum threshold to avoid storage limits is 400 but treating 400 as the target leaves no buffer. A score between 400 and 550 is vulnerable to capacity cuts during inventory build periods or if a slow quarter temporarily depresses sell-through rate.

Experienced FBA operators target 550 plus as the operating range. This provides enough buffer to absorb seasonal swings, new product launches with slower initial velocity, and Q4 inventory building without risk of crossing below the penalty threshold.

The weekly routine that maintains 550 plus:

Check Fix Stranded Inventory every Monday and resolve any new issues before they accumulate.

Review the Inventory Age report every two weeks and flag any ASIN approaching 60 days of supply with below-average velocity. Initiate price adjustments or removal orders before the 90-day excess inventory flag triggers.

Set a reorder quantity that delivers 30 to 45 days of supply per replenishment rather than 60 to 90 days. Larger less frequent orders improve cash flow but generate excess inventory flags. Smaller more frequent orders maintain IPI but require more active replenishment management.

Monitor your IPI score trend week over week not just the current value. An IPI dropping from 600 to 520 over four weeks signals an operational problem before it crosses the 400 threshold. The trend is more actionable than the point-in-time value.

For the complete connection between IPI score, low-inventory fees, and the FNSKU-level fee changes that took effect in 2026 see FBA Low Inventory Fee.

Rates verified July 22, 2026. See changelog.

FAQ

Q: What is the Amazon FBA IPI score threshold in 2026?
A: The minimum IPI score to avoid FBA storage limits is 400. Below 400 Amazon restricts your monthly cubic foot storage allocation, may impose ASIN-level restock limits on individual SKUs, and charges overage fees on inventory already in fulfillment centers above the new limit. The threshold was reduced from 450 in previous years. Amazon adjusts this threshold quarterly so always verify the current threshold in Seller Central under Inventory Performance. Target 550 plus as your operating range to maintain a buffer above the penalty threshold. Use the FBA Fee Calculator to model storage costs at different inventory levels.

Q: What are the four components of the Amazon IPI score?
A: The four components Amazon surfaces in Seller Central are excess inventory percentage, sell-through rate, stranded inventory percentage, and in-stock rate. Amazon does not publish the exact formula or weightings but excess inventory percentage and sell-through rate carry significantly more weight than the other two based on consistent seller community observation. Excess inventory percentage measures units flagged as overstocked based on 90 days of supply. Sell-through rate measures the percentage of total FBA inventory sold and shipped over the trailing 90 days. Stranded inventory percentage measures inventory in FBA that is not actively listed. In-stock rate measures the percentage of time products were available for purchase over the past 30 days.

Q: How do I improve my Amazon IPI score quickly?
A: Address the four components in order of speed. First fix all stranded inventory immediately using the Fix Stranded Inventory tool in Seller Central. Listing errors can be resolved within 48 hours. Second reduce excess inventory on slow-moving SKUs through price reductions, removal orders, or Amazon liquidations. Target Days of Inventory of 30 to 45 days across your active catalog. Third right-size replenishment quantities to maintain in-stock rate without generating excess inventory flags. Fourth allow 4 to 10 weeks for the rolling 90-day performance window to reflect the improvements. Recovery from a starting score of 350 typically takes 6 to 10 weeks of focused remediation.

Q: When does Amazon evaluate IPI scores for storage limits?
A: Amazon evaluates your IPI score during the last six weeks of each quarter to determine storage limits for the following quarter. IPI updates weekly but reflects rolling 90-day performance. A seller with a low IPI entering Q3 (July through September) will have restricted Q4 storage capacity regardless of improvements made after the evaluation window closes. This timing means sellers should monitor IPI actively starting in August to ensure Q4 capacity is not restricted. See FBA Reorder Point Formula for the inventory planning framework that keeps stock levels in the optimal range for both IPI health and low-inventory fee avoidance.