Amazon Changed My Dimensions and My FBA Fee Went Up

One morning the fee is $7. The next morning it is $17, on the same ASIN, with nothing changed in your listing. If Amazon changed my product dimensions and my FBA fee went up, the cause is almost always a remeasurement: Amazon's equipment recorded a size or weight that differs from yours, the product crossed into a higher size tier, and every unit shipped since then has been billed at the new tier.

Nobody emails you when it happens. There is a claim window, it is short, and it starts on the day of the charge, not the day you notice.

Why the fee went up when nothing changed

Amazon periodically remeasures inventory in the fulfillment centre. The measurement Amazon records takes precedence over the dimensions you entered, and it is what the fee is calculated from.

Size tiers are boundaries, not slopes. A fraction of an inch or a few ounces either side of a tier edge does not move the fee a little; it moves it to the next tier's rate. That is why sellers report doublings rather than drifts. One seller on the Seller Forums documented a fulfillment fee going from $40.43 to $88.93 per order across 29 orders, about $1,392. A Canadian seller documented $10.37 to $26.71 across 163 units, about $2,772, of which only $161.96 came back.

The thread with the most sellers behind it is blunter still: Amazon TRIPLES weight and dimensions of product I am selling carries 160 votes and 27 replies, and the reported margin went from 20% to 1%.

None of this is Amazon acting against you. It is an automated measurement that was wrong and a billing system that did exactly what it was told.

How long you have to claim the overcharge

Ninety days from the date the fee was charged. An Amazon representative answering a remeasurement question on the Seller Forums named the same window twice over: reimbursements commonly fail because the higher fees were not within 90 days, or because the remeasurement did not move the size tier at all.

Amazon staff set out the conditions on a separate thread about FBA charging 4 lbs on a 1.1 lb product:

• The request goes in within 90 days of the fee charge.
• The product has not been remeasured twice in the past 60 days.
• Units are available at the fulfillment centre to be measured.
• Your account has not exceeded its monthly remeasurement limit. Sellers in the forums report that limit as roughly 20 requests a month; treat the number as seller-reported.

The written policy lives in Seller Central under FBA fees reimbursement policy: Weight and dimensions.

Ninety days sounds generous until you notice the clock starts at the charge. If a remeasurement happens in late September and you catch it in your December close, the earliest units are already out.

Did Amazon silently hike your FBA fees?

Check my fees

Fixing it, step by step

1. Pull the FBA Fee Preview report for the whole catalogue. It lists the dimensions and weight Amazon has recorded, the size tier and the estimated fulfillment fee for every SKU. This is the screen where a remeasurement becomes visible, and it is the one to export and date-stamp monthly.

2. Compare Amazon's recorded dimensions against your own measured carton. Measure the packaged unit as it ships, not the bare product. Weigh it on a scale you trust.

3. Open a case for a remeasurement. Sellers report filing it under the FBA product weights and dimensions category and asking explicitly for a cubiscan verification of the unit at the fulfillment centre. That is seller-reported practice, not published procedure, so state the facts plainly and let support route it.

4. File the fee reimbursement as a separate request. A corrected measurement fixes the fee going forward. It does not automatically return what you were already charged. Ask for both, and say so in writing.

5. Attach the arithmetic, not the complaint. The sellers who get paid supply a line-by-line list: order ID, date, fee charged, corrected fee, difference. The ones who do not tend to supply a paragraph.

Expect friction. One seller was told the overcharge stood because the fee was correctly calculated on the measurements held at the time. Appeals inside the 90 days are how that gets tested; appeals after it are not.

How to stop it recurring

Export the FBA Fee Preview report on a fixed day every month and keep the file. Two dated exports side by side turn a hunch that the fee moved into a provable date. Without them, you are arguing from memory inside a 90-day window.

Watch tier edges, not fees. A SKU sitting close to a size tier boundary is the one that will cost you. Those are the SKUs worth measuring properly at the packaging stage.

Do the check before Q4, not during it. Fulfillment fees are only one of the Q4 costs that move without a listing change: peak fulfillment rates start October 15, monthly storage jumps on October 1, and the fuel and logistics surcharge rides on every unit. A wrong size tier multiplies all three.

Treat this as the same bucket as reimbursements. It is money already taken with a deadline on getting it back, exactly like the units you can no longer claim after a prep or labeling error.

Where SellerKey fits

SellerKey reads your Amazon fee and inventory data and shows when a SKU's recorded size tier and fulfillment fee changed, with the date, so a remeasurement surfaces while the 90 days are still open. It does not change your listings, your dimensions or your cases. It shows you the number; the case is yours to open.

#fees#fba#reimbursements#size-tier

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