Quick answer. The costliest FBA inventory mistakes are sending more stock than demand supports, letting units age into the surcharge, leaving sellable units stranded without an active offer, and running out of your best sellers. Amazon measures all four in the Inventory Performance Index (IPI), and the IPI is one of the inputs to your monthly FBA capacity limits. Amazon’s guideline is to hold enough inventory for 30 to 60 days of expected sales, it treats more than 90 days of supply as excess, and it charges an aged inventory surcharge on units stored 181 days or longer. The fix is a monthly routine built around Amazon’s own dates and reports.

Inventory problems rarely trigger a suspension on their own. They drain cash through storage fees and surcharges, shrink the room Amazon gives you to ship, and create the stockouts, listing errors and unreimbursed losses that wear down an account. Each mistake below maps to a metric Amazon already tracks, which means each one is visible in Seller Central before it becomes expensive.

How Amazon Measures Your Inventory

Amazon describes the IPI as a metric that gauges how efficient and productive you are in managing FBA inventory over time. The score and the Inventory Performance dashboard are available to sellers on the Professional selling plan. The dashboard grades four areas, each shown as Excellent, Good, Fair or Poor, and each area has a button that opens the tool where you act.

Newly created ASINs do not affect the IPI in their first 90 days. Amazon’s IPI FAQ also says a score requires a Professional plan, inventory in a fulfillment center and recent activity, so new FBA sellers, accounts inactive for the past 13 weeks and sellers using FBA only for Multi-Channel Fulfillment may not have one.

Two features of the score shape how you should work it. The IPI weighs long-term performance alongside recent performance, so one good month does not erase a poor quarter. And the dashboard shows which week the current score reflects, so the number you see trails the actions you took. We read the four bars against last month’s saved copy before reacting to the headline score, because the category that moved tells you which mistake to fix.

Mistake One, Sending More Than You Can Sell

Amazon considers an item excess when it has more than 90 days of supply based on forecasted demand. Your excess inventory percentage is the share of your FBA units identified as excess. The dashboard also shows excess units, which Amazon calculates as units where doing nothing and paying storage costs you more than acting, and an estimated total storage cost, which projects the monthly storage fees and aged inventory surcharges you would pay over three years if the stock sat untouched.

Excess usually starts with a freight decision. A seller orders six months of a product in one container to lower the landed cost per unit and sends it all to Amazon at once. The freight savings are real. So are the storage fees, the lower sell-through and the capacity the stock occupies while it waits.

How to fix excess

Amazon’s guideline is to keep enough stock for 30 to 60 days of expected sales. For units already over that, Amazon points to four options, and each fits a different situation.

• Price reduction. Works when the product sells at a lower price and the margin can carry it. It lifts sell-through without removing anything.
• Amazon Outlet deals. Moves a block of excess units to shoppers looking for markdowns, without permanently repricing the main offer.
• Multi-Channel Fulfillment. Uses the stock to fill orders from your other sales channels, so the units sell without discounting on Amazon.
• Removal orders. The right call when the cost of keeping a unit exceeds what it will sell for. Removals also come off your capacity usage within 24 hours of creation.

If supplier terms force large orders, hold part of the stock in your own or a third-party warehouse and send to Amazon on its restock recommendations. That keeps the freight savings and keeps the excess out of Amazon’s network.

Mistake Two, Letting Inventory Age Into the Surcharge

Amazon charges an aged inventory surcharge, previously called the long-term storage fee, on units stored in its fulfillment network for 181 days or longer. It is assessed from an inventory snapshot on the 15th of each month and charged on top of the monthly storage fee. Aged stock costs you twice, once in the fee and once in the IPI.

How Amazon counts age

Amazon calculates age first-in, first-out across its whole network. When any unit ships or is removed, Amazon deducts it from your oldest units, regardless of which physical unit moved. A steady seller can still accumulate aged units if it keeps sending fresh stock faster than the oldest stock sells, because the oldest units stay at the front of the count.

The rates

Amazon’s page, as updated for changes effective January 16, 2026, sets the surcharge per cubic foot and raises it with age. It starts at $0.50 per cubic foot for items aged 181 to 210 days, excluding certain apparel, shoe, bag, jewelry and watch items in the lower bands. It reaches the greater of $6.90 per cubic foot or $0.30 per unit for 366 to 455 days, and the greater of $7.90 per cubic foot or $0.35 per unit for 456 days or more. These are US figures and Amazon revises the table, so confirm current rates on Amazon’s fee page before you budget.

The deadline that matters

A removal or disposal order submitted before the cleanup deadline avoids that month’s surcharge, even if the units have not physically left the building. Amazon’s deadline is 11:59 p.m. Pacific time on the 14th. The FBA Inventory tool shows which ASINs are or will become subject to the surcharge within 60 days, which gives you two snapshots of warning. Amazon’s IPI FAQ recommends removing inventory before it reaches 365 days, and Amazon lets you set up automated removals for aged stock.

The decision for each aging SKU is sell, recover or remove. Sell means a markdown or deal large enough to clear the units before the snapshot. Recover means moving the units to another channel through Multi-Channel Fulfillment or a removal to your own warehouse. Remove means a removal or disposal order when neither of the first two is worth the cost. Make the decision with the 60-day warning, not on the 14th.

Mistake Three, Ignoring Stranded Inventory

Stranded inventory is sellable product in a fulfillment center with no active listing, so customers cannot buy it while it keeps incurring fees. Amazon lists it as one of the four IPI areas and states that inventory incurring fees with no possibility of sale can reduce your score. Stranded units are often the cheapest points to win back, because the product is fine and only the offer is missing.

The Fix stranded inventory page lists each SKU and the reason it is stranded. Common causes are a missing or out-of-range price, a closed offer, a suppressed listing, or a listing that went inactive after a catalog change. We sort every stranded SKU into one of three actions.

1. Reactivate. Where the cause is a listing error that can be corrected, fix it on the Fix stranded inventory page and confirm the offer is active and buyable.
2. Resolve. Where a compliance, safety or account matter blocks the ASIN, the units stay stranded until the underlying issue is cleared with genuine documents or a real correction. If the documents Amazon asks for do not exist, the honest answer is removal, not a relist.
3. Remove. Where the units cannot be made sellable, remove them before they age further. Check the removal address first, because it cannot be changed once the order is created.

Stranded inventory left for weeks becomes aged inventory, and aged inventory becomes a surcharge. Check the page weekly, not when the IPI drops.

Mistake Four, Running Out of Best Sellers

The in-stock rate is the percentage of time your replenishable FBA ASINs were in stock during the last 30 days, weighted by units sold for each SKU in the last 60 days. The dashboard also estimates FBA lost sales for out-of-stock days, which puts a dollar figure on the stockout.

Amazon’s IPI FAQ adds an important clarification. The in-stock rate itself is not a direct input into the IPI, and a low in-stock rate does not hurt the score unless your most popular products keep running out while the products that remain in stock sell slowly or are excess or aged. The pattern Amazon penalizes is the one that comes from a cash squeeze. A seller ties up money in slow stock, cannot afford to reorder the fast sellers, and ends up with the worst mix in the warehouse.

Tools that prevent stockouts

• Restock today. This button flags SKUs whose days of supply are shorter than your restock lead time.
• Restock Inventory. This page gives recommended quantities based on forecasted demand and your lead time.
• Hide non-replenishable SKUs. If a SKU is not meant to be reordered, hide its recommendation so it does not count against your in-stock rate.

Running too lean has its own cost. In the US, Amazon’s fee schedule includes a low-inventory-level fee for some products whose supply runs short relative to unit sales. Read the current criteria and exemptions on the FBA fee pages before you cut stock to the minimum.

Mistake Five, Not Planning Around Capacity Limits

Amazon sets one FBA capacity limit for each storage type each month, measured in cubic feet. The storage types are standard-size, oversize, apparel, footwear and extra-large. Amazon says the limit is influenced by your IPI score, historical sales volume, seasonal and peak periods for your products, ASIN forecasts, new selection, scheduled deals, fulfillment center capacity and shipment lead time. Limits are typically announced in the fourth week of the month, by email and in the Capacity Monitor at the bottom of the FBA dashboard.

Account rules

• Individual selling accounts have a fixed limit of 15 cubic feet that cannot be increased.
• New Professional accounts active in FBA for less than 39 weeks do not receive capacity limits, so Amazon can learn how much capacity the business needs.
• Each storage type is enforced separately, and capacity cannot be exchanged between types. Spare oversize room does nothing for a full standard-size limit.

What blocks a shipment

If on-hand inventory plus inbound shipments exceeds your limit, Amazon blocks new shipments in that storage type. You are also blocked when you are under the limit but the units you are trying to send would push you over. Three rules explain most cases where a seller believes the Capacity Monitor is wrong. Open shipment plans you never intend to send count toward usage until you cancel them in the Shipping Queue. Removal orders come off usage within 24 hours of creation, even while still pending. Customer returns are added back to usage when they are received.

To size a product, multiply length by width by height in inches and divide by 1,728. A unit measuring 47 by 12 by 10 inches is about 3.3 cubic feet, which is the example Amazon uses.

Capacity Manager

Capacity Manager lets you request more space for a future period that has a confirmed or estimated limit. You set the maximum reservation fee per cubic foot you are willing to pay, and Amazon grants requests in order of fee, highest first, until available capacity is allocated. Once the period starts, you earn a $0.15 performance credit for every dollar of FBA sales generated using the additional capacity, prorated by the share of your total limit the increase represents. If the credits do not cover the fee, you pay the balance. Amazon’s own advice is to skip the request if you are not confident you can sell the inventory and offset the fee.

See also Amazon IPI Score and FBA Capacity Limits.

Mistake Six, Shipping Inventory That Breaks the Rules

Inventory that does not meet FBA product, packaging or labeling requirements may be refused at the fulfillment center, repackaged or relabeled for a fee, or disposed of at your expense, and it is not eligible for reimbursement. The cost lands on a shipment you already paid to send. Packaging errors also cause damage in storage and transit, and units damaged because of inadequate packaging are your loss, not Amazon’s.

Barcode problems are the most common version of this mistake. A unit labeled with the wrong FNSKU, or a manufacturer barcode used where Amazon expects its own label, can be received against the wrong SKU or commingled in ways that complicate an authenticity question later. See our guide to the facts every FBA seller should know and Amazon’s barcode rules.

Mistake Seven, Never Reconciling What Amazon Received

Units go missing between your warehouse and a sellable status in Amazon’s network. Shipments are received short, units are lost or damaged inside a fulfillment center, and customer returns are refunded without the unit coming back. Amazon has reimbursement policies for many of these cases, but each has its own window and evidence requirement, and Amazon does not pay for what you never claim.

The records that decide a claim are the ones you keep at the time of shipping. Keep the supplier invoice, the packing list, the carrier’s proof of delivery and the shipment ID for every inbound shipment, and compare what Amazon reports as received against what you sent within days, not months. Our Amazon inventory reconciliation service reviews your FBA records for lost, damaged and unreimbursed units. To keep the rest of your account in good shape, see our account health maintenance service.

Every document you submit must be genuine and match the shipment it describes. Never alter, recreate or backdate an invoice, a packing list or a proof of delivery. A fabricated document in a reimbursement claim is an integrity problem that reaches the whole account.

When Inventory Problems Become Account Problems

Most inventory mistakes stay in the fee report. A few cross into account health. A shipment flagged for missing safety documents can leave units stranded and an ASIN blocked. A pattern of mislabeled units can feed an authenticity or condition complaint. Recalled products are held, and Amazon says that if you do not create a removal order within 30 days of the notification, the units will be disposed.

First-time versus repeat problems

A first IPI drop or a single surcharge month is an operational correction. Find the category that moved, trace it to SKUs, fix it and record the date. A repeat pattern is a process failure, such as excess every quarter after the same bulk order or stranded units every time a listing is edited. That calls for a written control with an owner, for example a rule that stranded inventory is reviewed every Monday by the listings manager. Where an inventory issue has already produced an account health notice, the response follows the same structure Amazon expects in any plan of action, with the root cause, the corrective actions already taken and the preventive controls.

Regional Differences in the US, UK and EU

The IPI, stranded inventory tools and restock recommendations work the same way across marketplaces. Fees and capacity are set per marketplace, and Amazon publishes a separate fee schedule for each. The surcharge rates quoted above are US rates. Before you plan around a fee in the UK or EU, read that marketplace’s own fee pages in its Seller Central.

In Europe, where you store inventory has tax consequences. Storing goods in a country through Pan-European FBA or other multi-country programs can create VAT registration and filing obligations in that country. Confirm the obligations for each storage country with a qualified tax adviser before you enroll. Units in Amazon’s network remain your inventory for accounting purposes in every region, so removals, disposals and liquidations also need to be recorded correctly. This is educational information, not legal or tax advice.

A Monthly Routine That Prevents These Mistakes

The routine below is built around two dates Amazon publishes, the surcharge snapshot on the 15th and capacity announcements in the fourth week. It takes a few hours a month for a catalog of moderate size.

1. Days 1 to 5, measure. Export FBA Inventory, the stranded list, Restock Inventory and last month’s aged inventory surcharge report, and save them with the date. Record the IPI, the week it reflects and the four performance bars. Record usage and remaining capacity for each storage type.
2. Days 5 to 10, decide. Sort every stranded SKU into reactivate, resolve or remove. List every ASIN that will be subject to the surcharge within 60 days and decide sell, recover or remove. Flag excess SKUs over 90 days of supply and choose markdown, Outlet, Multi-Channel Fulfillment or removal. Cancel open shipment plans you will not send.
3. Days 10 to 14, execute. Submit removal and disposal orders before 11:59 p.m. Pacific time on the 14th. Launch the markdowns and deals. Reactivate stranded listings and confirm each one is buyable.
4. Days 15 to 22, verify. When the surcharge bills, reconcile the report to your removals. Place reorders for replenishable best sellers from Restock Inventory, sized to 30 to 60 days of expected sales.
5. Fourth week, plan capacity. Read the capacity announcement and the Capacity Monitor for the coming months. Request more space in Capacity Manager only for proven sellers with a fee you can offset.
6. End of month, log. Write down what went wrong and the control that prevents it, with an owner and a date.

Expect the score to lag the work. Once a removal or liquidation is placed, those units are no longer considered in the IPI, but Amazon notes the score takes time to reflect it. Three or four consistent months show whether the routine is working.

Frequently Asked Questions

What is a good amount of FBA inventory to hold?

Amazon’s guideline is enough to cover 30 to 60 days of expected sales. More than 90 days of supply based on forecasted demand is treated as excess.

When does Amazon charge aged inventory fees?

The aged inventory surcharge applies to units stored 181 days or longer, assessed from a snapshot on the 15th of each month. A removal or disposal order submitted before 11:59 p.m. Pacific time on the 14th avoids that month’s charge.

Does my IPI score affect how much I can send to Amazon?

Yes. Amazon says your capacity limit is influenced by your IPI score along with sales history, forecasts, seasonality, scheduled deals, shipment lead time and fulfillment center capacity.

What is stranded inventory?

Sellable units in a fulfillment center that have no active listing and therefore cannot be purchased. They still incur storage fees and count against your capacity.

Do removal orders improve my IPI?

Once a removal or liquidation is placed, those units are no longer considered in the IPI, though Amazon notes the score takes time to reflect it. Removals also leave your capacity usage within 24 hours of creation.

Get Your Inventory Reviewed

Submit your case for a free assessment, or book a consultation.

See also Amazon FBA Mistakes and Their Bitter Consequences and FBA Inventory Reimbursements.

Get Help With Your Amazon Case

Our Amazon inventory reconciliation team can take the case from here. If the account itself is restricted, start with our Amazon suspension service. You can also see all our marketplace suspension services.

Sources

• Amazon Seller Central, Inventory performance
• Amazon Seller Central, IPI frequently asked questions
• Amazon Seller Central, FBA capacity limits
• Amazon Seller Central, Capacity Manager
• Amazon Seller Central, Aged inventory surcharge
• Amazon Seller Central, Remove inventory overview
• Amazon Seller Central, Product packaging requirements