How Amazon Calculates FBA Fees — And How to Check the Number Yourself

The three fees on every FBA sale, plus two that show up later

Every FBA sale carries two fees no matter what you sell, and picks up more depending on how the product moves through Amazon's warehouses.

• Referral fee — a percentage of the item's selling price, set by category, running from 5% to 45% on Amazon's published schedule — most general merchandise sits at 15%, Consumer Electronics at 8%, Amazon Device Accessories at 45% — with a $0.30 per-item minimum in most categories and price breakpoints inside several of them.
• FBA fulfillment fee — a flat rate per unit set by the package's size tier and weight, not the product's raw dimensions. Amazon measures the box that ships, not the item inside it.
• Monthly storage fee — charged per cubic foot of space your inventory occupies in a fulfillment center, with a materially higher rate in the October-December peak window than the rest of the year.

Two more fees only show up when something goes wrong or sits too long: an aged inventory surcharge once stock has been in a fulfillment center past a set number of days, and a removal or disposal fee if you pull inventory out or let Amazon dispose of it. Neither is a routine cost of selling — both are a sign the inventory plan slipped somewhere upstream.

A worked example: pricing a $24.99 kitchen item

Rates change often, so treat this as a method, not a lookup table — the mechanics stay the same even when the numbers move.

Say you sell a $24.99 kitchen item that weighs 1.2 lbs packaged and falls in the standard-size tier. A general-merchandise referral fee around 15% takes roughly $3.75. A standard-size fulfillment fee for that weight might land near $4.50. Add a monthly storage charge based on the cubic feet the packaged unit occupies — a small amount outside peak season, several times that in Q4. Subtract your landed cost and inbound shipping, and what's left is your real per-unit margin, not the number on the listing page.

This is exactly what Amazon's Revenue Calculator does, and it's the right first stop for one product. The problem shows up at catalog scale: run the same product through with the actual packaged dimensions the warehouse receives, rather than the dimensions on your product spec sheet, and the fee tier — and the margin — frequently changes.

Where sellers get the number wrong

The fulfillment fee is where most sellers lose the estimate, and it's almost always the same root cause: the calculator was fed the product's dimensions instead of the packaged, shipped dimensions Amazon actually measures. A half-inch of extra poly bag or an unnecessary insert can push a unit into the next size tier, and the fee jumps with it, not gradually.

Across the more than $500M in managed revenue Full Circle has managed for 100+ brands, dimensional-weight misclassification is one of the most common and most fixable leaks — it's a data entry problem with a real dollar cost, not a pricing decision. Bulky, heavy categories feel it hardest: cookware, the category HexClad sells in, is a good example of where packaging weight and box dimensions decide the fee tier as much as the product itself does.

The other recurring mistake is treating the referral fee as flat across a catalog. It isn't — it varies by category and sometimes steps up or down at specific price points within the same category. Assume one flat percentage and every margin calculation downstream is wrong by a consistent amount, which is worse than being wrong randomly, because it hides in the average.

When the fee Amazon charged doesn't match what you calculated

If the fee Amazon actually charged doesn't match your estimate, check the packaged dimensions and weight Amazon has on file for that ASIN before assuming the calculator is broken — a mismeasurement at receiving is the most common cause, and it's correctable. Seller Central's Fee Preview report, under Reports, then Fulfillment, then Payments, shows what Amazon currently has recorded for every SKU. That's the number to reconcile against, not the Revenue Calculator's estimate.

If the dimensions on file are wrong, you can dispute it and request a re-measurement. If a shipment arrived short, damaged, or was lost inside a fulfillment center and the fee or reimbursement doesn't reflect that, that's a claim to file, not a fee to accept — a different problem from a miscalculated size tier. And if the leak you're actually chasing is in ad spend rather than fulfillment or storage costs, that's not a fee problem at all — that's a job for Dr. PPC, not an inventory tool.

Amazon's calculator vs a third-party one vs watching it continuously

Amazon's own Revenue Calculator and Fee Preview report are free, official, and the most accurate source for a single SKU at a single point in time — use them first. Third-party calculators like Yotpo's add product cost, shipping, and ROI on top of the fee estimate, useful for pricing decisions before you commit inventory, though they run on the same public fee logic Amazon does, wrapped in a friendlier profitability view.

What none of these tools do is watch the fee over time, catch it when Amazon's system misclassifies a package after the fact, or connect a fee error to the reimbursement claim it should trigger. That's a monitoring and recovery job, not a calculator job — it runs continuously, not once at listing time.

Dr. Stock, from Full Circle, is built for that ongoing side: catching FBA fee errors and dimensional-weight misclassification as they happen, chasing the reimbursement, and feeding it back into the inventory decision rather than leaving it as a line item nobody reconciles. Whether or not that's a fit for your business, the calculators above will get you an honest number today — checking it stays a recurring job either way.