Amazon FBA Calculator: Profit & Fee Estimator

How Amazon FBA fees are calculated

Amazon doesn't charge one fee — it charges a stack of them, and each is calculated on a different basis. That's why a product can look profitable on a spreadsheet and lose money in the account. Getting the estimate right means knowing which lever drives each line.

The referral fee is a percentage of the total sale price, set by category — 15% for most, 8% for many electronics, with a per-item minimum around $0.30. It's the easiest to predict and the one most sellers already budget for.

The FBA fulfillment fee is a flat per-unit charge driven by your product's size tier and shipping weight, not its price. This is where dimensions matter more than sellers expect: a light but bulky product is billed on dimensional weight, so an inch of extra packaging can push you into the next tier and cost more than the packaging saved. A 2026 fuel and inflation surcharge of roughly 3.5% sits on top.

Storage is charged monthly per cubic foot and is seasonal — roughly $0.78 from January to September, jumping to about $2.40 in the October–December peak. Inventory that sits past 181 days picks up an aged-inventory surcharge on top. Then there's inbound placement, charged when you send stock to fewer receiving centers than Amazon would like.

What Amazon's own calculator leaves out

Amazon's Revenue Calculator stops after referral, fulfillment, and storage. Those are real, but they're the predictable part. The two lines that actually decide whether a product works — advertising and returns — aren't in it at all.

Advertising is the bigger of the two for most sellers. At a 20% ACoS, ads take another fifth of revenue before you've counted a single fee. Returns cost you twice: the refunded sale, plus stock that often can't be resold. Leave both out and a product showing a 30% margin can land closer to 5%.

This calculator includes both by default, which is why its number tends to be lower — and closer to what shows up in your bank account. For the full line-by-line breakdown with current rates, see our Amazon FBA fees breakdown.

A worked example: a $34.99 product

Take a standard-size product selling for $34.99 that costs $10.00 landed (product plus inbound freight and duty), weighing about a pound. Here's how the stack resolves:

Counting only product cost, referral, fulfillment, and storage, the same product shows about $13.54 — a 39% margin. The realistic figure is $4.79, or roughly 14%. Same product, same price: the difference is entirely the two lines the official tool omits.

Which fees you can actually control

• Dimensions and packaging — the fastest lever. Shrinking a carton below a size-tier threshold cuts the fulfillment fee on every unit you will ever sell.
• Inventory velocity — storage and aged-inventory charges are a function of time. Faster turns, especially before the Q4 rate jump, cost less.
• Advertising efficiency — a lower ACoS drops straight to net. This is usually the single biggest controllable line.
• Price — referral scales with it, but so does gross. Model both, don't assume raising price raises profit proportionally.
• Category — referral rates vary from 8% to 15%; a product's classification can be worth several points of margin.

Beyond the US, and beyond the browser

The same engine covers Amazon Germany and Japan, where VAT and consumption tax change the arithmetic — see the Japan fee guide if you're pricing in yen. If you'd rather not use a form at all, the same calculation is available as a free developer API, or as an MCP server you can call directly from Claude, Cursor, and other AI tools.