Amazon IPI Score & Restock Limits: How to Never Run Out of Inventory

What Is the IPI Score and Why It Controls Your Business

The Inventory Performance Index (IPI) is Amazon's scoring system that measures how efficiently you manage your FBA inventory. It's a number between 0 and 1,000, and it directly determines how much storage space Amazon will give you.

Think of it as a credit score for your inventory management. A high IPI score means Amazon trusts you to use warehouse space efficiently, so they give you more of it. A low score means you're wasting their space with slow-moving or stranded inventory, so they restrict your capacity and charge you overage fees.

Amazon evaluates your IPI score every quarter. The two critical check dates are at the end of Q1 (March) and Q3 (September), which set your storage limits for the following quarter. Miss the threshold and you'll be operating with restricted storage right when you need it most.

How Amazon Calculates Your IPI Score

Amazon doesn't publish the exact formula, but they do tell you the four factors that influence it. Each factor is weighted differently, and understanding the relative importance of each one is the key to improving your score quickly.

1. Excess Inventory (Highest Impact)

Excess inventory is stock that has been sitting in Amazon's warehouses longer than it should based on your sales velocity. Amazon defines excess inventory as units where the cost of holding them exceeds the cost of taking action — running a sale, creating a removal order, or liquidating.

Amazon uses the Excess Inventory Percentage, which is the percentage of your FBA units that Amazon considers excess. They calculate this by comparing your current stock levels against your trailing 90-day sales velocity and forecasted demand.

• Target: Keep excess inventory below 5% of total FBA units.
• What Amazon flags: Units with more than 90 days of supply based on current sell-through rate.
• Why it matters most: Excess inventory occupies space Amazon could give to faster-moving products. They penalize you for it with aged inventory surcharges and IPI score reductions.

2. FBA Sell-Through Rate (High Impact)

Sell-through rate measures how quickly your inventory sells relative to how much you're storing. Amazon calculates it as units sold and shipped over the past 90 days divided by the average number of units available in FBA during that period.

A high sell-through rate tells Amazon you're using warehouse space efficiently. A low rate means you're sitting on dead stock.

• Target: Maintain a sell-through rate above 7 units per week for every 1,000 units stored (or roughly 2-3 inventory turns per quarter).
• What tanks it: Sending in massive shipments before you have the demand to support them, or keeping seasonal products in FBA during off-season months.
• How to read it: Check the FBA Inventory Age report in Seller Central. Sort by sell-through rate to identify your worst performers.

3. Stranded Inventory (Medium Impact)

Stranded inventory is stock sitting in Amazon's warehouse that isn't available for sale. It's the most fixable factor — and the most frustrating to discover because it means you're paying storage fees on units that can't generate revenue.

Common causes of stranded inventory:

• Listing errors: A listing gets suppressed due to a missing image, restricted keyword, or compliance issue. Your inventory is still in FBA but can't be purchased.
• ASIN deleted or merged: Amazon merges your listing into another ASIN or deletes it, leaving inventory orphaned.
• Pricing errors: Your price falls outside Amazon's acceptable range (too high or too low relative to recent pricing) and the listing gets deactivated.
• Compliance blocks: A product requires approval, certifications, or safety documentation that has expired or wasn't submitted.

• Target: Keep stranded inventory rate at 0%. This should always be zero.
• How to check: Seller Central → Inventory → Fix Stranded Inventory. Set up automatic notifications so you catch stranded inventory within 24 hours.

4. In-Stock Rate (Medium Impact)

In-stock rate measures the percentage of time your replenishable ASINs have been in stock over the past 30 days, weighted by the trailing 60-day sales volume of each ASIN. Products that sell more are weighted more heavily.

This factor rewards sellers who keep their best-selling products consistently available. A stockout on your top-selling ASIN hurts this metric far more than a stockout on a slow mover.

• Target: 95%+ in-stock rate on all replenishable ASINs.
• What kills it: Running out of stock on your top sellers, long lead times from suppliers without buffer stock, and not accounting for FBA check-in delays.
• The paradox: Amazon wants you to keep high in-stock rates but also limits your storage capacity. Balancing these two demands is the central challenge of FBA inventory management.

IPI Thresholds and Storage Limit Tiers

Amazon sets IPI thresholds that determine whether your storage is restricted or unrestricted. These thresholds have shifted over the years as Amazon manages warehouse capacity.

The practical impact is massive. A seller with an IPI of 550 might receive 50,000 cubic feet of storage, while the same seller with an IPI of 320 might be limited to 15,000 cubic feet. That difference can mean the inability to stock your full catalog or prepare for seasonal demand.

How Restock Limits Work in 2026

Amazon overhauled its restock limit system in recent years, moving from separate storage type limits to a unified capacity limit system. Here's how it works now.

Capacity Limits Explained

Instead of separate limits for standard-size, oversize, apparel, and footwear, Amazon now provides a single capacity limit measured in cubic feet. This limit covers all storage types combined — inventory on hand, inbound shipments, and units reserved for processing.

Your capacity limit is based on three factors:

1. Your IPI score: Higher scores earn more capacity.
2. Your sales volume: Sellers with higher historical sales velocity get more space because Amazon expects them to move inventory faster.
3. Seasonal adjustments: Amazon may increase limits heading into peak seasons like Q4 if your IPI justifies it.

How Capacity Is Calculated

Your total capacity usage includes:

• On-hand inventory: Units currently at FBA fulfillment centers.
• Inbound inventory: Units in shipments that are shipped, checked in, or receiving — even if they haven't been stowed yet.
• Reserved inventory: Units reserved for customer orders, FC transfers, or FC processing.

This means you can't game the system by creating large inbound shipments right before a capacity check. Inbound units count against your limit from the moment you create the shipment in Seller Central.

Capacity Monitor Dashboard

Amazon provides a Capacity Monitor in Seller Central that shows your current usage, your estimated limits for the next period, and how much headroom you have. Check this dashboard weekly at minimum — daily during peak inventory replenishment periods.

The dashboard also shows your estimated capacity limit for the upcoming quarter, which is based on your current IPI trajectory. If you see that number dropping, you have time to take corrective action before the quarter ends.

Strategies to Improve Your IPI Score

Improving your IPI score isn't about one dramatic fix — it's about consistently managing the four factors. Here are the highest-impact strategies ranked by effectiveness.

Eliminate Excess Inventory First

This has the biggest impact on your IPI score. Go through your inventory and take action on every ASIN that Amazon flags as excess:

• Run a sale or coupon: Even a 10-15% discount can accelerate sell-through enough to clear excess status within 2-3 weeks.
• Create removal orders: For products that are truly dead, remove them from FBA. The removal fee ($0.97-$1.50 per unit for standard-size) is almost always cheaper than continued storage fees and IPI damage.
• Liquidate: Amazon's FBA Liquidations program lets you recover some value from unsellable inventory. You'll get pennies on the dollar, but it's better than paying to store products that won't sell.
• Donate: Amazon's FBA Donations program lets you donate excess inventory to charity. You don't recover costs, but you eliminate the storage fees and get a potential tax deduction.

Boost Sell-Through Rate

Sell-through rate is a ratio — you can improve it by selling more units or by reducing the number of units stored. Ideally, do both.

• Right-size your shipments: Instead of sending 90 days of inventory at once, send 30-45 day batches more frequently. This keeps your on-hand count lower while maintaining in-stock status.
• Use PPC to accelerate slow movers: If a product has the margins to support it, running a PPC campaign specifically to improve sell-through can be worth the ad cost when you factor in IPI improvement.
• Bundle slow movers with fast movers: Create multi-packs or bundles that combine a slow-moving product with a popular one. This moves units faster and creates a new listing with its own demand.
• Adjust pricing dynamically: Use repricers or manual price adjustments to keep sell-through rates healthy. A slightly lower price that maintains consistent sales is better for your IPI than a higher price that leads to stagnant inventory.

Fix All Stranded Inventory Immediately

This is the easiest IPI factor to fix — and the most common one that sellers neglect. Check the Fix Stranded Inventory page in Seller Central and resolve every issue:

• Relisting: If a listing was deactivated, fix the issue (add missing images, correct pricing, submit required documentation) and relist.
• Creating a removal order: If the listing can't be fixed, remove the stranded inventory immediately.
• Matching to a new listing: If the ASIN was deleted, create a new listing and match the stranded inventory to it.

Maintain High In-Stock Rates

This factor requires proactive replenishment planning rather than reactive ordering:

• Set reorder points for every ASIN: Calculate your reorder point as (daily sales velocity x lead time in days) + safety stock. Trigger a replenishment order when inventory hits this level.
• Account for FBA check-in delays: During peak periods, FBA can take 2-4 weeks to receive and stow inventory. Build this into your lead time calculation.
• Use Amazon's restock recommendations: The Restock Inventory page in Seller Central provides replenishment suggestions. These aren't perfect, but they're a good starting point — adjust based on your knowledge of seasonal trends and upcoming promotions.
• Prioritize top sellers: Since in-stock rate is weighted by sales volume, a stockout on your #1 product impacts your IPI far more than a stockout on a slow mover. Allocate your limited capacity to your best performers first.

Managing Excess Inventory: Removals, Deals, and Liquidation

Excess inventory is the single biggest IPI killer. Here's a detailed breakdown of every tool Amazon gives you to address it, plus strategies that go beyond the basics.

Removal Orders

Removal orders pull inventory out of FBA and either ship it back to you or dispose of it. Current removal fees for 2026:

When deciding between return and disposal, do the math. If the product costs less than the return shipping fee and has no resale value outside Amazon, disposal is the financially rational choice — even if it feels wasteful.

FBA Liquidations

Amazon's FBA Liquidations program sells your excess inventory to liquidation wholesalers. You typically recover 5-10% of your average selling price, which is low but better than paying ongoing storage fees and IPI penalties.

When to use liquidation:

• The product is still functional but demand has permanently declined.
• You've tried promotions and price reductions without meaningful improvement.
• The aged inventory surcharge exceeds the product's margin.
• You need to free up capacity quickly for better-performing inventory.

Outlet Deals and Lightning Deals

If your excess inventory is still viable product, use Amazon's promotional tools before resorting to removal or liquidation:

• Amazon Outlet: List overstock items on the Amazon Outlet page. Products need a minimum discount of 20%. This reaches bargain-hunting shoppers and moves units faster than standard price drops.
• Lightning Deals: Pay the deal fee ($150-500 depending on timing) and offer a deep discount for a limited time. The promotional velocity can clear weeks of excess inventory in a few hours.
• Coupons: Less aggressive than deals but consistently effective. A visible coupon badge increases click-through and conversion, accelerating sell-through on slow movers.

Fixing Stranded Inventory: A Complete Playbook

Stranded inventory is a zero-revenue, pure-cost problem. Every day inventory sits stranded, you're paying storage fees on units that can't sell. Here's how to prevent and fix it systematically.

Prevention

• Never let listings go stale: Keep all required listing attributes up to date. Amazon frequently updates listing requirements, and a field that was optional last month might be required now.
• Monitor listing health daily: Seller Central's Account Health dashboard and Listing Quality Dashboard flag issues before they cause suppression.
• Keep compliance documentation current: If you sell products that require safety certifications, FDA registrations, or other compliance documentation, track expiration dates and renew proactively.
• Set up automated alerts: Use the Selling Partner API or third-party tools to get instant notifications when a listing goes inactive or gets suppressed.

Resolution Process

When you find stranded inventory, follow this process:

1. Identify the cause: Go to Inventory → Fix Stranded Inventory. Amazon will show you why each unit is stranded (listing closed, suppressed, etc.).
2. Fix listing issues: If the listing was suppressed, address the specific violation — missing image, restricted keyword, pricing error, etc. Relist and wait for Amazon to reactivate (usually 24-48 hours).
3. Contact Seller Support: If the stranded inventory is due to an ASIN merge, catalog error, or other Amazon-side issue, open a case immediately. Be specific about the FNSKU and ASIN involved.
4. Create a removal order as a last resort: If you can't fix the listing within 7 days, remove the inventory. The storage fees on unsellable units aren't worth the wait.

Capacity Manager: How to Request More Storage

Amazon's Capacity Manager is a tool that lets you request additional storage capacity beyond your standard limits. It works as a reservation system where you commit to a maximum fee you're willing to pay for extra space.

How Capacity Manager Works

1. Submit a request: Specify how much additional capacity you need (in cubic feet) and the maximum reservation fee you're willing to pay per cubic foot.
2. Amazon evaluates: Amazon reviews requests and grants additional capacity based on available warehouse space, your IPI score, and your bid amount.
3. Performance credits: Here's the important part — you earn performance credits based on the sales you generate using the additional capacity. If you sell enough, your reservation fee can be reduced to zero. Amazon refunds up to 100% of the reservation fee based on sales performance during the period.

Bidding Strategy

The Capacity Manager operates on a bid system. Here's how to approach it:

• Start conservative: Begin with a reservation fee of $0.10-$0.15 per cubic foot. Many requests are granted at lower bids, especially outside of Q4.
• Calculate your ROI: Determine how much revenue the additional inventory would generate. If 1,000 extra cubic feet lets you stock $50,000 worth of product, even a $2.00/cubic foot reservation fee ($2,000 total) is easily justified.
• Time your requests: Submit requests early in the quarter for the best chances of approval. Waiting until capacity is tight reduces your odds and may require higher bids.
• Focus on proven products: Request capacity for ASINs with strong sales history. You'll earn performance credits faster, offsetting the reservation fee.

3PL Strategies for Overflow Inventory

Even with a perfect IPI score, Amazon's capacity limits may not accommodate your full inventory needs — especially for seasonal businesses or rapidly growing brands. A third-party logistics (3PL) provider is the solution.

The FBA-3PL Hybrid Model

The most effective approach is to use a 3PL as a staging warehouse that feeds inventory to FBA in controlled batches:

1. Ship bulk inventory to your 3PL: Receive full container loads or large wholesale orders at your 3PL warehouse.
2. Prep and label at the 3PL: Have your 3PL handle FNSKU labeling, poly-bagging, bundling, and any other FBA prep requirements.
3. Send controlled shipments to FBA: Based on your reorder points and capacity limits, have the 3PL send replenishment shipments to FBA every 2-3 weeks.
4. Keep 60-90 days of inventory at the 3PL: This buffer ensures you can quickly replenish FBA without waiting on international shipping or manufacturing lead times.

Choosing a 3PL Partner

Not every 3PL understands Amazon. Look for these qualifications:

• Amazon FBA prep experience: They should know FNSKU labeling, suffocation warning requirements, poly-bagging standards, and Amazon's shipment creation workflow inside and out.
• Proximity to Amazon FCs: A 3PL located near major Amazon fulfillment center clusters (Southern California, the Inland Empire, Dallas-Fort Worth, or the Pennsylvania/New Jersey corridor) reduces transit times and shipping costs for inbound shipments.
• Inventory management software: Your 3PL should have a WMS that integrates with Amazon's API, providing real-time visibility into 3PL stock levels alongside your FBA inventory.
• Scalability: Ensure they can handle your peak season volume, which may be 3-5x your average monthly throughput.

Multi-Channel Fulfillment as Backup

If your 3PL supports direct-to-consumer fulfillment, you can also use them as a backup for fulfilling Amazon orders via Seller Fulfilled Prime (SFP) or Merchant Fulfilled Network (MFN) when FBA capacity runs out. This keeps your listings active even if you can't send inventory to FBA.

Seasonal Storage Planning

Seasonal businesses face the hardest IPI challenge: you need massive storage during peak months but your off-season sell-through rate tanks, dragging down your IPI score right before you need capacity most. Here's how to navigate it.

The Q4 Storage Trap

The most common mistake is building inventory in Q3 for a Q4 peak. Your IPI is evaluated at the end of September, and if you've loaded up on inventory for Black Friday and Christmas without the Q3 sales to match, your sell-through rate craters. Amazon then restricts your Q4 capacity at the exact moment you need it most.

The Seasonal Storage Playbook

1. Clean house in Q2: Aggressively remove slow movers and excess inventory between April and June. This sets you up with a healthy IPI going into the June 30 evaluation.
2. Stage at 3PL in Q3: Ship your Q4 bulk inventory to a 3PL in July-August, not to FBA. Keep your FBA inventory lean to maintain strong sell-through and IPI scores through the September evaluation.
3. Ramp FBA in October: Once your Q4 capacity limits are set (based on your strong September IPI), begin sending inventory to FBA in controlled batches throughout October.
4. Use Capacity Manager for the gap: If your standard capacity isn't enough for Q4, use Capacity Manager to bid for additional space. Your Q4 sales velocity will likely earn back the reservation fee through performance credits.
5. Post-Q4 cleanup in January: Remove any remaining seasonal inventory from FBA by mid-January. Don't let Christmas inventory sit in FBA until March — the aged inventory surcharges and IPI damage aren't worth it.

Advanced IPI Tactics for High-Volume Sellers

If you're already above the 400 threshold and want to maximize your capacity allocation, here are advanced strategies:

SKU-Level Inventory Optimization

Analyze every SKU's contribution to your IPI score:

• Rank all ASINs by inventory health: Create a spreadsheet combining sell-through rate, days of supply, and excess inventory status for every ASIN. Sort by "IPI drag" — the products that are hurting your score the most.
• Set ASIN-level max inventory rules: For each product, calculate the maximum FBA quantity that maintains a healthy sell-through rate. Never exceed this number, even if you have capacity available.
• Kill zombie SKUs: Products that sell fewer than 1 unit per week with more than 30 days of supply are IPI anchors. Either invest in marketing them or remove them from FBA entirely.

Shipment Timing Optimization

The timing of your inbound shipments affects your IPI calculation:

• Don't send large shipments right before IPI evaluation dates. A massive inbound shipment that arrives at the end of September inflates your on-hand count before it can generate sales, temporarily tanking your sell-through rate.
• Front-load shipments early in the quarter. This gives the inventory time to sell through and improve your sell-through metric before the evaluation date.
• Use AWD (Amazon Warehousing & Distribution): Amazon's upstream warehousing service lets you store bulk inventory in Amazon's distribution centers without it counting against your FBA capacity limits. Amazon then automatically replenishes your FBA inventory based on demand signals.

Account Structure Considerations

For sellers with very large catalogs, consider how your product mix impacts your aggregate IPI:

• Every product category has different natural sell-through rates. If you sell both fast-moving consumables and slow-turning durable goods, the durables drag down your average sell-through. Consider whether separate accounts or removing durables from FBA makes sense.
• FBM for long-tail products: Products that sell 1-2 units per month don't belong in FBA. The storage costs and IPI impact outweigh the Prime badge benefit. Fulfill these through FBM or a 3PL with direct-to-consumer capabilities.

Bottom Line

Your IPI score isn't just an inventory metric — it's a bottleneck that determines whether you can keep your products in stock on the world's largest marketplace. The sellers who treat inventory management as a strategic function, not an afterthought, are the ones who never run out of stock during peak season. Clean up excess inventory ruthlessly, fix stranded inventory immediately, maintain strong sell-through rates, and use 3PL partners and Capacity Manager to bridge the gap between what Amazon gives you and what your business needs. Your IPI score is a lagging indicator of hundreds of small inventory decisions. Get those decisions right consistently, and the score takes care of itself.