Improve your IPI Score on Amazon: Tips & Tricks to maximize your sales

It is Tuesday morning in mid-October. You sip your coffee, log into Seller Central to check on your incoming holiday freight, and there it is.

The red banner.

Your storage capacity has been limited because your Inventory Performance Index (IPI) dipped below 400. Right when the Q4 rush is about to start, Amazon just tied your hands behind your back. You cannot send in your bestsellers. Your holiday launch strategy is effectively dead in the water.

Panic sets in.

If this scenario makes your stomach drop, you are not alone. Across the globe, brand managers and COOs are watching their logistics costs skyrocket because they treat their FBA inventory like a static spreadsheet. They ship containers, cross their fingers, and hope the algorithm treats them kindly.

But hope is a terrible supply chain strategy. With Amazon tightening the screws on storage fees and enforcing strict restock limits, understanding the IPI Amazon score is the only thing standing between a profitable quarter and a warehouse full of dead stock.

Here is where most sellers get it wrong. They treat the score as an unsolvable mystery. It is not. It is a math equation. And once you know how to balance it, you dictate your own growth.

The math Amazon does not want you to overthink

Amazon lists four factors that make up your IPI score: Excess inventory, Sell-through rate, Stranded inventory, and In-stock rate. They display them side-by-side on your dashboard, visually suggesting that each metric carries an equal 25% weight.

They do not.

Testing across thousands of seller accounts reveals a much harsher reality. Excess inventory and your 90-day sell-through rate combined make up the vast majority of your score—roughly 75 to 80 percent.

Think about it. Amazon is a logistics company, not a self-storage facility. They make money when boxes move off their shelves and into delivery vans. If your products sit there gathering dust, you are costing them money.

If you only have time to focus on one thing this week, ignore the green checkmarks and look directly at your sell-through rate. You calculate this by taking your total units shipped over the past 90 days and dividing it by the average number of units on hand in fulfillment centers during that same period. If that number falls below 2.0, your score is bleeding out.

This is precisely why aggressive Amazon listing optimization is your best defense mechanism. You cannot fix a sell-through problem purely from the supply chain side. If the traffic hitting your product page does not convert, inventory piles up. By dialing in your SEO, refining your A+ content, and increasing your conversion rate, you force inventory to move faster, naturally inflating your IPI score without pulling a single logistics lever.

The contrarian truth: 100% In-Stock is a trap

Ask any traditional retail manager how to run a business, and they will tell you to never run out of stock.

On Amazon in 2026, that advice will get you penalized.

Chasing a perfect 100% In-Stock rate is a dangerous trap. Here is why. To guarantee you never stock out during volatile demand swings, you have to pad your shipments with a heavy safety net. That safety net becomes excess inventory the second your sales velocity dips.

Your In-Stock rate metric might look beautiful, but your Excess Inventory percentage will drag your IPI below the critical 400 threshold. Once you drop below 400, your storage limits get slashed, making it impossible to send in enough of your actual fast-moving products. You effectively trade your most profitable items for the comfort of keeping slow-movers in stock.

Let a slow-moving SKU stock out. It is fine. Hide the recommendation in Seller Central so it stops dinging your In-Stock rate metric, and focus your capital on the top 20% of your catalog that drives 80% of your revenue.

The 35-day supply trap: balancing overstock vs. low-inventory fees

Just when sellers figured out how to stay lean, Amazon changed the rules of the game.

They introduced the low-inventory-level fee. Initially set at a 28-day threshold, Amazon bumped the floor to 35 days of historical supply in 2026. If you carry less than 35 days of inventory for a standard-size product, you get hit with a per-unit surcharge on every single sale.

This creates a brutal paradox.

If you understock, you pay the low-inventory penalty. If you overstock to avoid the penalty, your inventory ages past 90 days, your sell-through rate tanks, and your IPI drops below 400.

You are forced to walk a tightrope. The margin of error is basically zero. Managing this manually with Excel sheets and gut feelings is no longer mathematically viable. You need dynamic forecasting. You have to predict exactly how many units you will sell in the next 45 days, adjusting daily for PPC performance, seasonality, and organic rank shifts.

If you are running robust advertising campaigns, your demand will spike. Make sure you read these 8 tips to improve your Amazon advertising performance so you can actually accurately forecast the traffic surge before you send in your freight.

20-50% — The reduction in supply chain forecast errors achieved by companies deploying AI-driven forecasting at scale, directly protecting margins from overstock penalties. Source: McKinsey & Company

Why stranded inventory is the silent margin killer

Stranded inventory happens when your products are sitting in an FBA warehouse, but the listing is inactive, suspended, or deleted.

Customers cannot buy it. You cannot sell it.

But Amazon? They are still charging you monthly storage fees for every cubic foot it occupies.

Worse than the fees is the mathematical damage it does to your IPI. Stranded units count heavily against your excess inventory and drag your sell-through rate down to absolute zero for those specific items. A sudden batch of stranded inventory can drop a healthy 450 IPI score down to 380 in less than two weeks.

Fixing stranded inventory requires daily vigilance. Sometimes it is a simple pricing error where Amazon deactivated the listing due to potential high pricing. Other times, it is a Hazmat review or a sudden gating of a sub-category. Whatever the reason, you have two choices: fix the listing immediately, or submit a removal order.

Do not let it sit.

Manual spreadsheets vs. AI inventory control

Feature	Manual IPI Management	AI-Driven Optimization
Demand Forecasting	Static 30-day lookback via Excel	Real-time predictive analytics based on PPC and seasonality
Low-Inventory Fees	Reactive panic shipments	Automated alerts before dipping below the 35-day floor
Excess Mitigation	Slashing prices after 90 days	Dynamic pricing to clear slow stock at day 60
Stranded Inventory	Weekly manual Seller Central audits	Daily automated flagging and resolution workflows
IPI Trajectory	Rollercoaster drops during Q3/Q4	Stable, predictable growth above 500

What changed in 2025-2026

The landscape of FBA logistics shifted heavily over the last 18 months. Amazon is no longer subsidizing cheap warehouse space. They are forcing brands to operate with razor-sharp efficiency. If you are operating on a 2024 playbook, you are already losing money.

The 35-Day Low-Inventory Floor (Early 2026)

As mentioned earlier, the transition from a 28-day to a 35-day historical supply requirement caught thousands of brands off guard. Amazon implemented this because they want enough inventory to distribute your products across multiple regional fulfillment centers (minimizing their own shipping costs). If you fail to provide enough stock for them to co-locate, they pass the expedited shipping cost directly to you via this fee.

FBA Peak Fulfillment Fees Hike (October 2026)

Peak season has always been expensive, but the 2026 rate cards introduced an average increase of $0.08 to $0.10 per unit for standard-size items during the October-to-January window. For bulky items or products priced over $50, the fulfillment fee jumps even higher. If your IPI is low and you are forced into using a 3PL like eFulfillment Service to drip-feed inventory into Amazon, your logistics overhead effectively doubles during the most critical quarter of the year.

Aged Inventory Surcharge Escalation

The old “long-term storage fee” is gone. It has been replaced by aggressive aged inventory surcharges that kick in much earlier. Inventory sitting past 241 days now incurs massive monthly penalties. Large enterprise solutions like Blue Yonder or Amazon AWD (Amazon Warehousing & Distribution) are becoming standard workarounds for brands trying to hold bulk inventory upstream without getting crushed by FBA surcharges.

Epinium data: Brands actively optimizing their listing conversion rates and utilizing AI demand forecasting see an average IPI score jump of 47 points within the first 60 days of software adoption.

Frequently asked questions about your IPI

What is a good Amazon IPI score in 2026?

The absolute minimum threshold to avoid storage limits is 400. However, a “good” score that provides a comfortable buffer against sudden sales drops is anything above 500. If you sit above 550, you essentially unlock unlimited standard-size storage for your brand.

How often does Amazon update the IPI score?

Amazon recalculates and updates your IPI score every week, typically on Mondays. However, because it relies on a rolling 90-day window, actions you take today (like liquidating a massive chunk of excess inventory) might take a few weeks to fully reflect in a higher score.

Does closing a listing improve my IPI?

No. Closing or deleting a listing while the physical units are still sitting in an FBA warehouse simply turns that stock into stranded inventory. This immediately hurts your score. You must either sell through the stock or submit a removal/disposal order before closing the listing.

How do I fix stranded inventory quickly?

Navigate to the “Fix stranded inventory” page in Seller Central. Usually, Amazon provides a specific reason (e.g., “Listing error”, “Missing SKU”, “Restricted product”). Often, simply matching the SKU to an active ASIN or fixing a pricing alert resolves it within 24 hours. If it cannot be fixed, create a removal order immediately.

Can I pay to increase my FBA storage limit?

Yes and no. Amazon introduced the Capacity Manager system, which allows you to request additional storage space by bidding on a reservation fee. If your sales generated in that extra space meet certain targets, the fee is offset by performance credits. But it is a risky bet if your sell-through remains poor.

Why is my sell-through rate dropping even though sales are up?

Your sell-through rate is a ratio of units sold to units on hand. If your sales increased by 20%, but you sent in 50% more inventory in anticipation of a peak season, your denominator grew faster than your numerator. Your relative sell-through rate will drop until those sales catch up to your massive inventory injection.

Do multi-channel fulfillment (MCF) orders count towards IPI?

Yes. Any unit that ships out of an Amazon fulfillment center to a customer counts toward your shipped units metric. Using MCF to fulfill orders from your own Shopify store is a highly effective tactic to boost your 90-day sell-through rate without relying solely on Amazon marketplace traffic.

How do new ASINs affect my IPI score?

They do not affect it immediately. New ASINs are typically exempt from the IPI calculation for the first 90 days they are active in FBA. This gives you a grace period to launch the product, run aggressive PPC, and establish a baseline sales velocity without the fear of immediate excess inventory penalties.

What happens if I ignore the low-inventory fee?

If you continuously hold less than 35 days of supply, Amazon will deduct the low-inventory-level fee from your payout on every single unit sold. Over a high-volume month, this quietly erodes thousands of dollars from your net profit margin, effectively wiping out the profitability of low-priced items.

Moving faster than the algorithm

The days of treating Amazon as a set-it-and-forget-it sales channel are long gone. The algorithm is ruthless. It rewards efficiency and heavily penalizes bloat.

Your competitors are not manually downloading reports on Thursday afternoons anymore. They are utilizing AI to predict demand, automate pricing adjustments, and dynamically route inbound freight to avoid penalties before they happen.

If your team is still spending hours cross-referencing Seller Central dashboards trying to figure out why your capacity was cut, you are losing the operational war. By focusing heavily on your sell-through rate and keeping a razor-sharp eye on stranded units, you can push your IPI well into the green zone.

Stop letting a single metric throttle your revenue potential. Take control of your data, optimize your listings to drive velocity, and turn your supply chain from a cost center into a competitive advantage.