Quick answer. The FBA mistakes that cost sellers the most are quiet ones. A product measured or weighed wrong pushes every unit into a higher fee bracket. Stock left to age past 181 days triggers the aged inventory surcharge on top of monthly storage. Unfulfillable units sit until they are worth nothing, inbound shipments go unreconciled against what was received, and lost or damaged units go unclaimed past Amazon’s 60 day window. Each one is caught the same way. Every month, compare what you believe is true (your dimensions, your counts, your costs) against what Amazon’s reports say, and act on the gap before a deadline closes it. Dangerous goods and restricted products add a second layer, because the wrong classification changes fees and can remove your right to be reimbursed at all.

Most FBA sellers do not lose money in one dramatic event. They lose it a few cents per unit, for months, because a box was measured larger than it is or a report nobody opened listed units never paid for. By the time anyone notices, the claim window has closed.

Below we take each mistake against Amazon’s published rules, work a fee check with hypothetical numbers, and end with a monthly audit routine for Seller Central.

Why small FBA errors turn into large losses

FBA is a chain of linked calculations. Amazon’s product dimensions and volume page states that product dimensions and weight are critical inputs to the product size tier. They feed fulfillment fees, monthly storage fees, the aged inventory surcharge, removal fees, disposal fees, Multi-Channel Fulfillment fees, the inbound placement service fee and prep service fees. One wrong input creates a wrong fee everywhere that input is used, on every unit, every time the fee is charged.

Inventory compounds the same way. An unclaimed lost unit is a full loss of its sourcing cost, unfulfillable units occupy space you pay for, and aging stock climbs surcharge bands each month. None of this sends an alarm. It shows up only in reports someone has to open.

Fee mistakes. Paying for the wrong size and weight

The FBA fulfillment fee is a per unit charge applied when the buyer’s order ships. Amazon’s fee page says the rate depends on product type, size tier and shipping weight. For 2026 Amazon has also announced a 3.5% fuel and logistics surcharge on FBA fulfillment fees in the US and Canada starting April 17, 2026, and holiday peak fulfillment fees from October 15, 2026 to January 14, 2027, with the surcharge applying to those peak fees as well. If your measurements are wrong, every one of those layers is calculated on the wrong base.

How shipping weight is decided

Amazon’s shipping weight page sets the rule. Dimensional weight is the unit volume (length times width times height, in inches) divided by 139. For core FBA products other than apparel and dangerous goods, Amazon uses the greater of unit weight or dimensional weight for large standard size, large bulky and most extra-large units. Small standard size units, and extra-large units over 150 lb, use unit weight. For large bulky and extra-large items, dimensional weight assumes a minimum width and height of 2 inches.

That last rule catches flat products. Amazon’s own example is a 40 x 1 x 25 inch dry erase board weighing 4.5 lb. With the 2 inch minimum, its dimensional weight is 40 x 2 x 25 divided by 139, or 14.4 lb, and that becomes its shipping weight.

Packaging is a fee decision

Amazon publishes an example in which reducing a box from 12.2 x 12.0 x 4.3 inches to 12.2 x 12.0 x 3.2 inches, with the same 3.6 lb unit weight, lowered the dimensional weight from 4.52 lb to 3.4 lb and moved the item from the 4.5+ to 4.75 lb range down to the 3.5+ to 3.75 lb range. Only the packaging changed.

Amazon’s numbers win

Amazon’s dimensions page says it may verify weight and dimensions using representative samples, and where its information differs from yours, its information is used to calculate fees. What matters is what Amazon has on file now and whether it is right, not what you entered.

A fee check, worked through with hypothetical numbers

The figures below are invented for illustration. The formulas, the 139 divisor, the 1,728 cubic inch conversion and the surcharge and removal rates come from Amazon’s pages as read in October 2026. Confirm current rate cards before acting.

The setup

A seller ships a kitchen product. Their own measurement of the packaged unit is 14 x 10 x 4 inches at 2.1 lb. In the Monthly Storage Fees report, the item-volume field for the FNSKU shows about 825 cubic inches, consistent with Amazon having the unit on file at 15 x 11 x 5 inches. Assume the item falls in large standard size, which the seller confirms on Amazon’s product size tier guidance, so the greater of unit weight or dimensional weight applies.

What the gap costs

Now the fulfillment fee. Suppose, for illustration, the rate card shows $6.10 for the 4 lb bracket and $6.95 for the 6 lb bracket. At 1,200 units a month, that $0.85 gap costs $1,020 a month before the 3.5% surcharge and peak rates. Add 0.153 extra cubic feet of storage per unit and a higher removal fee, and one inch of disagreement becomes a five figure annual problem.

What to do with the result

If your genuine measurement is smaller than Amazon’s, Amazon’s fee pages direct you to the FBA Remeasurement and Reimbursement Tool to check whether the product is eligible for remeasurement and reimbursement. Measure several sealed units first and keep dated photos. If Amazon’s figure is right, the fix is packaging, not a claim. Never submit dimensions you have not measured on the unit you ship.

The aged inventory surcharge and how it escalates

Amazon’s aged inventory surcharge (previously called the long-term storage fee) applies to units stored in the fulfillment network for 181 days or longer, in addition to the monthly storage fee. Amazon assesses it from an inventory snapshot on the 15th of each month and says the charge typically lands between the 18th and 22nd.

The rate bands

From January 16, 2026, Amazon’s published US rates are $0.50 per cubic foot for 181 to 210 days, $1.00 for 211 to 240 days, $1.50 for 241 to 270 days (these first three bands exclude clothing, shoes, bags, jewelry and watches), then $5.45 for 271 to 300 days, $5.70 for 301 to 330 days and $5.90 for 331 to 365 days. From 366 to 455 days the charge is $6.90 per cubic foot or $0.30 per unit, whichever is greater, and from 456 days it is $7.90 per cubic foot or $0.35 per unit, whichever is greater. At day 271 the per cubic foot rate more than triples from one band to the next.

Age is counted first in, first out

Amazon counts age first in, first out across the whole network. A sale or removal comes off your oldest units, whichever unit physically shipped, so a fresh replenishment never resets the clock on old stock.

A hypothetical surcharge

Take the kitchen product above at the seller’s correct 0.324 cubic feet. 400 units aged between 366 and 455 days cost 400 x 0.324 x $6.90 = $894.24 by the cubic foot method, versus 400 x $0.30 = $120 by the per unit method. Amazon charges the greater, $894.24, every month the stock stays. A removal at $6.07 a unit costs $2,428 once. If those units will not sell within about three months, removal is cheaper than waiting, before even counting monthly storage.

The 14th of the month deadline

Amazon’s surcharge page states that if you submit a removal or disposal order before the cleanup date, that inventory will not incur the aged inventory surcharge even if it is not physically removed by then. The deadline to submit is 11:59 p.m. Pacific time on the 14th of the month. Amazon also recommends the FBA Inventory tool to spot ASINs that will be subject to the surcharge within 60 days, and suggests Outlet deals (minimum 20% discount) or automated removals.

Removal and disposal fees. The price of leaving it too late

Removal and disposal are charged per unit, based on size tier and shipping weight, and since March 1, 2026 Amazon charges them at the time each unit is removed or disposed of. Amazon’s current US rate card for standard size items is $0.84 for 0 to 0.5 lb (from January 15, 2026), $1.53 for 0.5+ to 1.0 lb, $2.27 for 1.0+ to 2.0 lb, and $2.89 plus $1.06 per lb above 2 lb for anything over 2 lb. Large bulky, extra-large and special handling items start at $3.12. Amazon lists apparel, shoes, watches, jewelry and dangerous goods as examples of special handling items, so a hazmat classification also moves you onto the more expensive removal card.

Rounding matters. For standard size tiers under 1 lb, Amazon rounds shipping weight up to the nearest 0.1 lb. For the other tiers it rounds up to the nearest whole pound. A 0.56 lb unit is billed at 0.6 lb, and a 10.1 lb oversize unit at 11 lb.

Timing is not instant

Amazon says removal orders are typically processed in 14 business days, may take 30 business days or more during the holiday season and peak removal periods, and take another two weeks for carrier delivery. Plan removals well before peak, and reconcile what arrives against the removal order detail report.

Letting unfulfillable inventory sit

Unfulfillable units are stock that cannot be sold as new, such as customer damaged returns, warehouse damaged units, and defective or expired goods. They do not sell, they occupy space you pay for, and every month they sit makes the decision worse.

What the reimbursement policy says about them

Amazon’s reimbursement policy excludes items pending disposal or disposed of at your request or by Amazon, and items that are defective or customer damaged. For items already unsellable when lost, damaged or removed, it reimburses a reduced estimated cost. If Amazon’s handling made units unsellable, claim before you dispose, because disposal ends eligibility.

Sorting the pile

Sort by cause. Warehouse damaged units should appear in the Inventory Defect and Reimbursement portal or Inventory Ledger and may be claimable. Customer damaged or defective units are not reimbursable, so remove or dispose of them deliberately. Customer returns follow different reimbursement rules, which we cover in our guide to FBA return reimbursements.

Stranded inventory is a cousin of the same mistake

Stranded inventory is sellable stock with no active offer to sell it against, because the listing was suppressed, closed or blocked by a compliance flag, or a pricing problem took the offer down. We sort every stranded unit into one of three actions. Reactivate where the listing can be restored, because that returns units to selling fastest. Resolve where a compliance or account block can be cleared with genuine documentation. Remove where neither is possible, before the units age into surcharges. Repeated stranding on the same ASINs means the real fix is the listing or compliance problem. Our earlier article on inventory management mistakes covers capacity limits and stranded stock in more depth.

Not reconciling inbound shipments and network losses

Reconciliation is where most recoverable money sits. Amazon’s policy says it replaces or reimburses items lost or damaged at a facility or by a carrier operated by or on behalf of Amazon, and many losses are reimbursed without a claim. The job is knowing which losses were paid, at what value, and which were missed.

The four places a unit can go missing

Amazon’s policy separates claims into four types, each with its own process. They are shipment to Amazon claims, fulfillment center operations claims, customer return claims and removal claims, and each needs different proof. An inbound shortage is proven with your shipping plan, packing lists and carrier proof of delivery. A warehouse loss is proven by the unit’s history in the Inventory Ledger, showing it arrived, was not sold, returned or removed, and is no longer there. A removal shortage is proven by comparing the removal order against what you received.

The eligibility conditions sellers trip over

Amazon’s policy lists conditions every claim must meet. The ones that most often defeat inbound claims are these. You must have sent the exact items and quantities stated in your shipping plan. The shipment must not be in canceled or deleted status. The item must comply with FBA product restrictions and inventory requirements. And your account must be in normal status when you file and while the claim is reviewed. Count before you seal and fix the plan before shipping.

The method. Unit by unit

We work every loss the same way. Pull the Inventory Ledger and the Inventory Defect and Reimbursement portal. For each FNSKU, reconcile units received, sold, returned, removed, disposed of and reimbursed. Any remaining gap is a candidate. Each candidate must show in the ledger that it entered the network, be unexplained by any sale, return or removal, not already be reimbursed, and still be inside the window. We claim only units that pass every test.

Missing reimbursement windows and undervaluing your claims

For fulfillment center operations claims, Amazon requires submission no later than 60 days after the date the item was reported lost or damaged in the Inventory Defect and Reimbursement portal or Inventory Ledger, and late claims are not eligible. A valid claim filed on day 61 is worth nothing.

How Amazon values a reimbursement

Amazon values a claim by timing. For losses before a customer order (shipment to Amazon, fulfillment center operations and removal claims), it reimburses sourcing cost, meaning your cost to buy or produce the item, excluding shipping, handling, customs duties and other costs. If you do not enter a cost on the Manage Your Sourcing Cost page, Amazon uses its own estimate based on comparable products. Customer return claims are valued on the refund or replacement minus applicable fees. The cap is $5,000 per unit.

Supplying your sourcing cost honestly

If Amazon’s estimate is below your real cost, submit your actual sourcing cost with genuine supplier invoices or production records. Amazon states it may decline a submission that is an outlier compared to similar products, where documentation is forged, tampered with or illegible, or where the account is suspected of fraud. Submit only what your records prove. An inflated cost turns a legitimate claim into an integrity problem.

Do not flood the queue

Amazon’s policy warns that insufficiently researched or premature requests, or a large number of requests in a short time, can lead to delayed support, monitoring, investigation and account action. Reconcile first, claim only genuine gaps, and file steadily. Amazon may also reverse a reimbursement if the unit is found, so track reversals too. If your account has already received a warning tied to reimbursement activity, read our overview of FBA account suspension reasons before filing anything else.

Dangerous goods classification surprises

A product you consider ordinary may be classified as a dangerous good because of what it contains, such as batteries or aerosols, and the surprise usually arrives after the inventory is made.

Why classification changes the economics

Amazon’s fee page makes dangerous goods status one of the steps for identifying which fulfillment rates apply, and adds fees for items containing lithium batteries. On the removal and disposal cards, dangerous goods are special handling items, priced from $3.12 per unit rather than the standard card. A hazmat classification can raise both fulfillment and exit costs.

How to check before you ship

Run every new ASIN through the Look up an ASIN tool and read Amazon’s dangerous goods identification guide before placing a production order. Keep the manufacturer’s Safety Data Sheet and battery documentation ready. If an existing ASIN is newly classified, pause inbound shipments until you understand the status. Documents must be genuine. If a supplier cannot provide them, you have a sourcing problem to solve, not a document to create.

Product restrictions that cancel your protection

FBA product restrictions are separate from category approvals. The less obvious consequence sits in the reimbursement policy. An item is only eligible for reimbursement if it complies with FBA product restrictions and FBA inventory requirements. Ship a restricted item and, if it is lost, you may have no claim at all.

Before sending anything new, check FBA product restrictions and FBA inventory requirements and keep a dated record. If a restriction lands on stock already in the network, treat it as stranded and either resolve it with genuine documentation or remove it before surcharges start. Our guide to restricted products you cannot sell explains the wider rules.

This article is educational information about Amazon’s published policies, not legal advice. Product safety, hazardous materials and labeling rules also come from government regulators, and where they apply to your product you should take advice specific to it.

When it has already gone wrong. Diagnose, correct, prevent

If you find a leak, do not file everything at once. Work it like a case.

Diagnosis and root cause

Quantify first, from the reports. Establish which ASINs or FNSKUs, which fee or claim type, how many units, since when, and which are inside the window. Then name the specific failure. “We were careless” is not a root cause. “The supplier changed the box in March and nobody re-measured” is. So is “Nobody owned the portal, so May’s defects aged past 60 days.”

Corrective action and preventive controls

Fix what can still be fixed and keep proof, such as the remeasurement request with dated photos, claims with transaction IDs, removal order IDs and the corrected shipping plan. Record anything outside its window honestly as a loss. Then give every control a named owner and a date. Operations measures three units of every new or changed SKU before the first shipment. The account manager works the Eligible for claim tab every Monday. The buyer decides aged stock by the 10th. A control with no owner is a hope.

A monthly FBA audit routine you can run

The routine follows the monthly fee calendar so every decision is made before the date that locks it in. Most sellers can finish it in a few hours once the reports are bookmarked.

Week one. Losses and claims

• Work the Eligible for claim tab oldest first so nothing crosses day 60.
• Check that each Resolved amount uses the right basis, and dispute only with records.
• Reconcile the Inventory Ledger for top FNSKUs, and last month’s inbound and removal shipments against your own counts.

Week two. Aged and stuck stock, before the 14th

• Filter FBA Inventory by age and list ASINs in or within 60 days of a surcharge band.
• Decide sell through, remove, dispose or wait, and submit orders before 11:59 p.m. PT on the 14th.
• Give every unfulfillable and stranded unit a decision.

Weeks three and four. Fees and prevention

• After the surcharge posts, compare the Aged Inventory Surcharge report with your week two list.
• Spot check fulfillment fees in Payments, Transaction View against your measured shipping weight.
• Run new products through the Look up an ASIN tool and FBA product restrictions before shipping.
• Log findings, fixes and the owner of each open item.

For a grounding in how the program works before you start this list, our FBA fundamentals guide covers the basics. If the reconciliation itself is the bottleneck, our team runs it as a service through Amazon inventory reconciliation, claiming only genuine, documented, in-window discrepancies.

See also FBA Inbound Placement Service Fee and FBA Inventory Reimbursements.

See also Amazon IPI Score and FBA Capacity Limits.

Frequently Asked Questions

When does the aged inventory surcharge start?

It applies to units stored in the fulfillment network for 181 days or longer, assessed from a snapshot on the 15th of each month, on top of the monthly storage fee.

How do I avoid this month’s aged inventory surcharge?

Submit a removal or disposal order before 11:59 p.m. Pacific time on the 14th. Amazon says that inventory will not incur the surcharge even if it has not physically left by the cleanup date.

What if Amazon measured my product wrong?

Measure several real packaged units and photograph the results, then use the FBA Remeasurement and Reimbursement Tool to check eligibility. Amazon uses its own measurements for fees when they differ from yours.

How long do I have to file a lost or damaged inventory claim?

For fulfillment center operations claims, you have 60 days from the date the item was reported lost or damaged in the Inventory Defect and Reimbursement portal or Inventory Ledger report. Other claim types have their own pages, so check each.

How much does Amazon reimburse for lost FBA inventory?

For losses before a customer order, Amazon reimburses sourcing cost, using its own estimate unless you provide your genuine cost. The maximum is $5,000 per unit.

Can I claim for units I have already disposed of?

No. Amazon’s policy excludes items pending disposal or disposed of at your request, so finish any claim before you dispose.

Does a dangerous goods classification change my fees?

It can. Amazon tells sellers to check dangerous goods status when identifying applicable fulfillment rates, adds fees for lithium battery items, and places dangerous goods on the higher special handling removal and disposal card.

Get Help With FBA Fees, Losses and Reconciliation

If your reports show gaps you cannot explain or claims stuck in review, our team can tell you what is recoverable. Submit your case for review, or book a consultation to walk through your FBA account before peak season.

This article is general educational information based on Amazon’s published help pages as read in October 2026. Fees, windows and policies change, so confirm current terms in Seller Central before acting. It is not legal, tax or financial advice, and no outcome, amount or timeline is guaranteed. Got Suspended? is not affiliated with Amazon.

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: FBA fulfillment fee
• Amazon Seller Central: Aged inventory surcharge
• Amazon Seller Central: FBA removal order fees
• Amazon Seller Central: FBA disposal order fees
• Amazon Seller Central: Product dimensions and volume
• Amazon Seller Central: Shipping weight
• Amazon Seller Central: FBA inventory reimbursement policy
• Amazon Seller Central: FBA inventory reimbursement policy, Fulfillment center operations claim