Amazon’s fulfillment network processes billions of units a year, and a measurable share of them get charged the wrong fee, go missing between receiving and the shelf, or come back from a customer and never reappear in sellable stock. Every one of those events is a line item a seller can audit, and most of them are recoverable through an Amazon FBA reimbursement claim if the seller finds the discrepancy inside Amazon’s claim window. This guide walks through where the money leaks, which Seller Central reports expose it, and how a claim is written so it gets approved on the first pass rather than bounced back for “insufficient information”.
In short
- Fee errors cluster in four places: wrong size tier or weight, inventory lost or damaged in the warehouse, customer returns that never land back in stock, and removal or disposal orders that go astray.
- Amazon reimburses some of it automatically, but the automatic process only catches events Amazon itself flags. Everything else needs a seller-filed claim.
- Claim windows shrank in late 2024. According to Amazon’s FBA inventory reimbursement policy, most warehouse loss and damage claims now have to be filed within 60 days of the event, and customer-return claims inside a defined window after the refund. Verify the current windows in Seller Central before relying on them.
- Four reports do most of the work: the Inventory Ledger, the FBA Customer Returns report, the Reimbursements report and the Fee Preview (or Fee Explorer) data.
- Reimbursement services charge 10% to 25% of recovered money. They pay for themselves on large, messy catalogs and rarely on small, clean ones.
Where do FBA fee errors most commonly occur?
Most recoverable money sits in four buckets, and they show up in different reports, which is why sellers who only look at one report miss the rest. The buckets are fulfillment fee errors caused by wrong dimensions, inventory that goes missing or gets damaged inside Amazon’s network, customer returns that are refunded but never checked back into sellable inventory, and removal or disposal orders that are lost in transit or executed incorrectly.
The first bucket is the most expensive per unit but the hardest to see, because a fee error does not appear as a discrepancy. The seller is simply charged a higher fulfillment fee on every unit of an ASIN, month after month, until somebody compares Amazon’s recorded dimensions against the real product. A product that measures 2 centimeters over a tier boundary can move from large standard to large bulky and roughly double its fulfillment fee. Amazon’s published rate card (in the FBA fees section of Seller Central) is the reference for what each tier costs, and those rates change at least annually.
The second and third buckets, warehouse loss and returns, show up as inventory events. They are easier to detect because Amazon logs them, but the logs are spread across the Inventory Ledger, the Inventory Adjustments report and the returns report, and the seller has to join them by FNSKU and date. Understanding how selling on global marketplaces allocates responsibility between the platform and the seller matters here: on Amazon the warehouse is Amazon’s, but the reconciliation burden is the seller’s.
Dimension and weight errors: how do you challenge them?
A dimension or weight error is a fulfillment-fee overcharge caused by Amazon’s recorded measurements for an ASIN being larger or heavier than the product actually is. Amazon measures inbound items with automated dimensioning equipment, and those measurements are periodically re-taken. Packaging changes, a bent carton, or a unit measured with a shipping polybag inflated around it all push a product up a tier.
How size tiers turn a small error into a large fee
FBA fees are stepped, not linear. A product is assigned to a size tier based on its longest side, median side, shortest side, and either unit weight or dimensional weight, whichever is greater. The fee for a tier applies to every unit in that tier, so crossing a boundary by a few millimeters changes the fee for the whole ASIN. The table below summarizes the structure sellers need to sanity-check; the actual boundary values and fees are published by Amazon in the FBA rate card and change over time, so always confirm the current figures there.
| Size band (structure) | What defines the boundary | Typical audit check |
|---|---|---|
| Small standard | Small, light items under a dimension and weight ceiling | Is the recorded weight above the real weight because of packaging? |
| Large standard | Most household and consumer goods below the bulky threshold | Is the longest side recorded above the real value? Is dimensional weight overriding unit weight? |
| Large bulky | Longer or heavier items above standard limits | Was a unit measured in an oversized outer carton? |
| Extra-large bands | Very heavy or very long items, multiple sub-bands | Is the item recorded in a heavier sub-band than its true weight? |
Dimensional weight is the trap that catches the most sellers. Amazon computes it as length times width times height divided by a divisor, and for larger items it uses dimensional weight when that exceeds actual weight. A light but boxy product (a pillow, a lampshade, a foam yoga block) can be billed as if it weighed several times its real mass. The right comparison is not “is the weight correct” but “which of unit weight and dimensional weight is Amazon using, and is the one it picked based on correct dimensions”.
Finding the mismatch in Seller Central
The starting point is Amazon’s own record of each ASIN’s dimensions, which is visible in the fee preview tools inside Seller Central and in the downloadable fee reports. Export the list, then compare against a physical measurement of the packaged unit as Amazon would receive it (in its retail packaging, not the case pack). A spreadsheet with four columns per ASIN (recorded length, width, height, weight) beside four columns of measured values, plus a computed size tier for each, will surface the ASINs where the tiers disagree.
Prioritize by monthly units. A 3-millimeter error on an ASIN that ships 40 units a month is not worth an hour of anyone’s time. The same error on an ASIN shipping 4,000 units a month is a four-figure monthly leak. Sellers who have read up on the trade-offs between FBA and FBM often run this analysis for a second reason: a persistent oversize misclassification can be the difference that makes FBM cheaper for that specific ASIN.
Requesting a remeasurement
Amazon provides a remeasurement request path through Seller Central, typically accessed via a Seller Support case under the FBA fee or product measurement category. The seller states the ASIN, the measured dimensions and weight, and ideally attaches photographs of the packaged unit on a scale and against a ruler or tape measure. Amazon then re-measures a unit in a fulfillment center and updates the record if its measurement agrees.
Two things about this process are worth knowing before filing. First, the remeasurement is forward-looking: it corrects future fees. Whether Amazon refunds past overcharges after a successful remeasurement varies, and sellers report that a separate fee reimbursement request, citing the corrected measurement, is usually needed to recover the historical overcharge. Second, if Amazon’s new measurement still disagrees with the seller’s, the seller can escalate with more evidence, but repeated remeasurements of the same ASIN without new evidence tend to get closed.
How do you reconcile lost, damaged and disposed inventory?
Inventory that enters Amazon’s network and is later lost, damaged, or disposed of by Amazon is generally eligible for reimbursement under Amazon’s FBA inventory reimbursement policy, subject to the seller proving the units existed and the loss happened on Amazon’s side. The reconciliation exercise is a units-in, units-out ledger per FNSKU, and the Inventory Ledger report in Seller Central is built for exactly that.
Reading the Inventory Ledger
The Inventory Ledger has a summary view (opening balance, receipts, customer shipments, returns, adjustments, closing balance, per FNSKU per period) and a detailed view that lists every event with a reason code. The audit logic is simple in principle: for each FNSKU, opening balance plus receipts plus returns minus shipments minus removals should equal the closing balance. Anything that does not balance is an adjustment, and each adjustment has a reason code that tells the seller whether it is claimable.
The event types that matter most are receipt discrepancies (Amazon received fewer units than the seller shipped), warehouse damage, warehouse loss, and disposals. Receipt discrepancies are handled through the inbound shipment reconciliation flow rather than a standard lost-inventory claim, and Amazon requires proof of what was shipped: the carrier’s proof of delivery, the packing list, and often a supplier invoice showing the quantity purchased.
Adjustment codes and what they mean for a claim
Amazon’s adjustment reason codes (single letters and short codes in the detailed ledger) distinguish between events like “found”, “lost”, “damaged”, “disposed” and “transferred”. A lost event that is later matched by a found event nets to zero and is not claimable. A lost event with no matching found event inside Amazon’s investigation period is the claim. Damaged events are claimable when the damage occurred in Amazon’s custody, which the ledger identifies by the location of the event.
The most common reconciliation mistake is claiming for lost units that Amazon later found and returned to stock. Amazon’s automatic processes usually catch these, mark the claim as ineligible and, if a reimbursement had already been issued, reverse it. Repeatedly filing claims that Amazon considers invalid is one of the behaviors that draws scrutiny on an account, and sellers who have dealt with an Amazon account suspension know the cost of that scrutiny is far higher than any single reimbursement.
What Amazon reimburses automatically
Amazon states in its policy that it proactively reimburses for inventory it identifies as lost or damaged in its fulfillment centers. In practice, automatic reimbursements cover a meaningful share of warehouse loss and damage, and the seller’s job is to check the Reimbursements report against the ledger to find the events that were never reimbursed. Sellers should not assume that “Amazon does it automatically” means “nothing is left”; the events Amazon misses are precisely the ones without a clean system flag, such as a unit damaged during a transfer between fulfillment centers.
A second point about automatic reimbursements: the value Amazon pays is set by its policy, not by the seller’s asking price. Amazon announced that from early 2025 its reimbursement for lost or damaged inventory would be based on an estimate of the product’s sourcing cost rather than its sales price, with a mechanism for sellers to provide their own cost figures. Sellers who believe Amazon’s estimate is too low can supply documentation, but the burden of proof is on the seller and the figures should be checked against the current policy text in Seller Central, since this policy has been revised more than once.
What happens to returns that never come back to sellable stock?
A customer return that Amazon refunds but never checks back into the seller’s inventory is one of the highest-yield claim categories, because the seller has lost both the sale and the unit. Amazon’s return policy gives customers a window to send the item back after a refund is issued, and Amazon itself allows a further period for the unit to be received and graded. If the unit never arrives, Amazon’s policy is to reimburse the seller, but only if the seller (or Amazon’s automatic process) identifies the gap.
Refund versus return: the timing gap
The audit here joins two reports: the FBA Customer Returns report (which lists every returned unit Amazon received, its disposition, and the date) and the refund data from the Payments or Transaction reports. Every refunded order in the returns-eligible window should have either a matching returned unit or, if the customer never sent it back, a reimbursement. Refunds with neither are the claims.
The disposition field on the returns report is where a second category of claim hides. A unit that comes back and is graded “customer damaged” is not reimbursable in most cases, because Amazon treats the damage as the customer’s. A unit graded “damaged” or “defective” where the seller can show it left the warehouse in good condition may be reimbursable, and a unit graded “sellable” that was refunded at full price while the customer kept it is a different scenario again. Sellers who have examined when a returnless refund is the cheaper option will recognize the economics: sometimes Amazon issues a returnless refund on the seller’s behalf, and the seller needs to check whether that unit’s cost was reimbursed.
The customer-return claim window
Amazon’s policy sets a specific window in which a seller can file a claim for a refunded unit that never came back, starting after the return-shipping deadline passes. According to the FBA inventory reimbursement policy Amazon published for the late-2024 changes, customer-return claims have to be filed between 60 and 120 days after the refund, with earlier filing rejected because the return is still in transit and later filing rejected as out of window. That framing means a monthly audit that only looks at last month’s refunds is too early; the sweet spot is refunds issued two to three months ago. Confirm the exact days in the current policy before building the schedule.
Which reports do you need and how do you read them?
Five reports, all in the Reports section of Amazon Seller Central, provide the data for a complete FBA fee audit. The table below lists each, where the money hides in it, and the field a seller should filter on first. Report names and locations shift as Amazon reorganizes Seller Central, so treat the names as the current ones at the time of writing and search the reports index if one has moved.
| Report | What it reveals | First field to filter | Claim category it feeds |
|---|---|---|---|
| Inventory Ledger (summary and detailed) | Every inventory event per FNSKU with reason codes; the balance check | Event type = adjustment; reason code = lost or damaged | Warehouse lost and damaged |
| FBA Customer Returns | Returned units received, their grade and disposition | Disposition; compare against refund list | Returns never received; grading disputes |
| Reimbursements | Every reimbursement Amazon has already issued, with reason and amount | Reason code; amount per unit | Excludes already-paid events from the claim list; flags under-valued reimbursements |
| Fee Preview or Fee Explorer data | Amazon’s recorded dimensions, weight, size tier and fulfillment fee per ASIN | Size tier; dimensional weight versus unit weight | Dimension and weight overcharges |
| Removal Order Detail | Units requested, shipped and delivered on each removal order | Requested quantity minus shipped quantity | Lost removals; disposals executed incorrectly |
The workflow that connects them is: pull the Inventory Ledger for the period, isolate every adjustment with a claimable reason code, then remove any event that already appears in the Reimbursements report. What remains is the warehouse claim list. Separately, join the returns report to the refunds list to build the returns claim list. Separately again, run the dimension comparison from the fee data. Three lists, three claim types, three different case categories in Seller Support.
How do you file a claim that gets approved?
A claim that gets approved on the first pass has three properties: it is filed under the correct case category, it cites the specific event by identifier, and it is inside the window. Amazon’s support agents work from a script that checks those three things before they look at the merits, so a claim with the right evidence but the wrong category still gets bounced.
Evidence by claim type
For a warehouse lost or damaged claim, the evidence is the Inventory Ledger line: FNSKU, event date, fulfillment center code, reason code and quantity. For an inbound receipt discrepancy, Amazon usually asks for proof of the quantity shipped (a carrier proof of delivery showing carton count and weight, and an invoice or packing list from the supplier). For a returns claim, the evidence is the order ID, the refund date, and the absence of a matching line in the returns report. For a fee overcharge, the evidence is the measured dimensions and weight with photographs, plus the ASIN and the fee cycle affected.
Wording should be factual and short. A claim that reads “On date, FNSKU X shows an adjustment with reason code lost at fulfillment center ABC1 for 12 units. No matching found event appears in the ledger through date, and no reimbursement for this event appears in the Reimbursements report. Requesting reimbursement for 12 units under the FBA inventory reimbursement policy” gives the agent everything the script asks for. A claim that reads “we are missing a lot of inventory, please check” gets a request for more information.
Claim windows at a glance
Amazon tightened its claim windows in October 2024, and the shorter windows are the single biggest reason sellers who audit quarterly now leave money on the table. The table below reflects the windows as published in Amazon’s FBA inventory reimbursement policy at that time. These figures are subject to change, and a seller should verify the current window for each claim type in Seller Central before relying on them.
| Claim type | Window (as published by Amazon, late 2024) | Window starts from |
|---|---|---|
| Lost or damaged in fulfillment center | 60 days | The date the inventory was reported lost or damaged |
| Customer return not received or not reimbursed | Filed between 60 and 120 days after the refund | The refund date |
| Removal order lost in transit | Reportedly 15 to 75 days after the removal shipment | The shipment creation date |
| Inbound shipment receipt discrepancy | Reconciliation window shown per shipment in Seller Central | The date the shipment is marked received or closed |
Why recovery belongs in the margin math
Sellers who compete hard on price to win the buy box without cutting margin should treat reimbursement recovery as part of the margin calculation. Two percent of FBA revenue recovered is two percent of margin that does not have to come from the sale price, and that matters more for a seller in a tight buy-box contest than for one with pricing headroom.
Reimbursement services: worth the percentage or not?
A reimbursement service is a third-party firm that runs the audit described above on the seller’s behalf, files the claims, and takes a percentage of whatever Amazon pays. Fees in the market typically run from around 10% to 25% of recovered money, with some vendors charging a flat monthly fee instead. The decision comes down to catalog complexity, the seller’s own labor cost, and how comfortable the seller is giving a third party access to the account.
What the services actually do
The better services connect to the seller’s account through Amazon’s Selling Partner API (with a scoped authorization), pull the same reports listed above on a schedule, run the reconciliation automatically, and then have a human file each claim. The automation is the value: a service that pulls the ledger daily will catch a 60-day event at day 3, while a seller who audits monthly may catch it at day 45 with the paperwork still to do. Amazon’s policies restrict how third parties interact with Seller Support, and reputable services file claims in a way that complies with those rules; a service that promises to “bulk file” thousands of cases via automation is a red flag, both for compliance and for the account’s standing.
When the percentage pays for itself
The economics are a simple comparison of the recovered amount net of the fee against the cost of doing it in-house. The table below frames the decision for three account profiles; the figures are illustrative and a seller should substitute their own.
| Account profile | Estimated annual recoverable | Service fee at 20% | In-house cost (staff hours) | Likely better option |
|---|---|---|---|---|
| Small: under $500k FBA revenue, under 50 ASINs, standard sizes | $3,000 to $8,000 | $600 to $1,600 | 2 to 4 hours per month, roughly $1,500 to $3,000 a year | In-house, using the reports directly |
| Mid: $500k to $5m, 50 to 500 ASINs, some oversize | $10,000 to $60,000 | $2,000 to $12,000 | 8 to 15 hours per month, roughly $6,000 to $12,000 a year | Either; service wins if the team is stretched |
| Large: over $5m, 500 or more ASINs, multiple marketplaces | $60,000 and up | $12,000 and up | A part-time or full-time analyst | Service or an in-house analyst with tooling |
What are the most common mistakes in an FBA fee audit?
The mistakes sellers make are consistent enough that they are worth listing as a checklist, in rough order of how much money each one costs.
- Auditing quarterly. With a 60-day window on warehouse claims, a quarterly audit forfeits roughly a third of warehouse events before anyone looks at them. Monthly is the minimum cadence and biweekly is better.
- Skipping the dimension audit. Inventory claims are visible as events; fee overcharges are invisible until someone measures a product. The dimension audit is usually the largest single recovery on a catalog with oversize or boxy items.
- Not subtracting existing reimbursements. Filing claims for events Amazon already paid produces denials, wastes agent time and, in volume, draws unwanted attention to the account.
- Filing returns claims too early. A refund from three weeks ago is still inside the customer’s return window; Amazon will deny the claim and the seller has to refile later.
- Ignoring removal orders. Removal shipments are rarely counted on receipt. Counting them is a ten-minute task per shipment and catches losses nothing else will.
- Losing the historical exports. Reports age out. An event a seller cannot show in a report is an event a seller cannot claim.
- Treating the audit as a one-time project. The value is in the routine. A single cleanup recovers old money once; a monthly routine recovers new money continuously and catches packaging drift before it costs a full year of fees.
Ranking pressure compounds several of these. Sellers focused on how Amazon ranks products know that stock-outs hurt rank, and an unrecovered lost-inventory event is a stock-out that the seller paid for twice: once in the unit cost and once in the lost sales velocity while the ASIN sat at zero.
FAQ on FBA fee audits and reimbursements
What is an Amazon FBA reimbursement claim?
An Amazon FBA reimbursement claim is a request filed by a seller asking Amazon to compensate them for inventory lost, damaged or disposed of inside Amazon’s fulfillment network, for a customer return that was refunded but never received, for a removal order that went missing, or for fulfillment fees charged on incorrect dimensions or weight. Amazon evaluates the claim against its FBA inventory reimbursement policy and, if approved, credits the seller’s account with either a replacement unit or a monetary reimbursement based on Amazon’s valuation.
How long do I have to file an FBA reimbursement claim?
It depends on the claim type, and the windows tightened in late 2024. According to Amazon’s published policy at that time, claims for inventory lost or damaged in a fulfillment center have to be filed within 60 days of the event, and customer-return claims have to be filed in a window that opens 60 days after the refund and closes at 120 days. Removal and inbound discrepancy claims have their own windows. Because Amazon revises these periods, the current figures in Seller Central are the authoritative ones and should be checked before building an audit schedule.
Does Amazon reimburse lost inventory automatically?
Partly. Amazon states that it proactively reimburses sellers for inventory it identifies as lost or damaged in its fulfillment centers, and the Reimbursements report in Seller Central shows every such payment. The automatic process does not catch every event, particularly losses during transfers between facilities and returns that never arrive, and it values units according to Amazon’s own cost estimate. The seller’s audit exists to find the events Amazon missed and to challenge valuations that appear too low.
How much does Amazon pay per reimbursed unit?
Amazon’s policy sets the reimbursement value, not the seller. Amazon announced that from early 2025 it would base reimbursements for lost or damaged inventory on an estimate of the product’s sourcing cost rather than its selling price, with a route for sellers to submit their own cost documentation if they believe the estimate is wrong. The exact valuation method and any caps are described in the current FBA inventory reimbursement policy, which should be consulted directly since the figures and mechanism have changed more than once.
How do I challenge FBA fees based on wrong dimensions?
Measure the packaged unit yourself (length, width, height and weight, in its retail packaging as Amazon receives it), compare against the dimensions Amazon records in the fee preview data, and if they disagree, submit a remeasurement request through Seller Central with photographs of the unit on a scale and against a tape measure. If Amazon’s remeasurement confirms the seller’s figures, the record is corrected for future fees. Recovering past overcharges usually requires a separate fee reimbursement request that references the corrected measurement.
What percentage do reimbursement services charge?
Most charge a percentage of the money recovered, commonly in the 10% to 25% range, and some offer a flat monthly subscription instead. Because most percentage-based services charge nothing if they recover nothing, the direct financial downside of trialing one is small. The real costs are the account access granted and the quality of the claims filed in the seller’s name, both of which deserve more scrutiny than the headline percentage.
Can I claim for a return the customer never sent back?
Yes, if the refund was issued and Amazon never received the unit back within the return window, Amazon’s policy provides for reimbursing the seller. The claim has to be filed inside the customer-return claim window, which under the late-2024 policy opens 60 days after the refund and closes at 120 days. The evidence is the order ID, the refund date and the absence of a corresponding line in the FBA Customer Returns report.
Next steps
The first month’s audit is the biggest, because it clears the backlog inside the current windows, and the second month’s is the one that establishes the routine. Export the five reports, build the three claim lists, and file inside the tenth of the month. Sellers expanding beyond Amazon will find the same discipline applies to every marketplace with a fulfillment program; the complete guide to selling on global e-commerce marketplaces covers how each platform’s fee structure and claim process compares, and where the reconciliation burden sits on each.
This article is general information for sellers and not accounting, tax or legal advice. Amazon’s fee schedules, reimbursement policies and claim windows change, and the current versions published in Seller Central take precedence over anything summarized here. Sellers with large or disputed claims should consult their accountant or an advisor familiar with marketplace terms for their specific situation.