Understand What Amazon Actually Charges

Amazon's fees on a single unit sale come from five sources. Getting the math wrong on any one of them produces an inaccurate margin:

Referral Fee: A percentage of the total sale price (including shipping if charged). Rates vary by category — typically 8% for electronics, 15% for most general merchandise, 17% for apparel, 20%+ for Amazon Device Accessories. The referral fee is charged on every sale regardless of fulfillment method.

FBA Fulfillment Fee: Charged per unit shipped, based on product dimensions and weight. A standard-size, 6-ounce product costs approximately $3.56 to fulfill (2026 rates). Oversized items cost significantly more. Know your product's enrolled size tier in Seller Central.

Monthly Storage Fee: Charged per cubic foot per month. Standard-size storage costs $0.78/cubic foot from January–September and $2.40/cubic foot from October–December. For a small item, this might be $0.03/month per unit at normal velocity. For a bulky item with slow turnover, storage can materially erode margin.

Long-Term Storage Fee (Aged Inventory Surcharge): Units stored 181–270 days incur a surcharge of $1.50/cubic foot/month. Units stored 271+ days incur $6.90/cubic foot/month. This fee punishes overstocking — build it into your slow-season assumptions.

Returns: Amazon allows customers 30 days to return most items. FBA return rates vary by category (apparel: 20–30%, electronics: 5–10%, home goods: 5–8%). Amazon refunds the customer but only partially refunds you — the return processing fee is typically $3–$5 per unit, and many returned items cannot be restocked as new.

How to Enter Your Numbers

Open the Amazon FBA Fee Calculator and fill in each field:

Selling Price: The price you will set on the listing. If you're deciding on pricing, run the calculator at 3–5 price points to see how margin changes.

COGS (Cost of Goods Sold): Your landed cost per unit — includes product cost from supplier, freight, import duties, and any prep fees. Many sellers forget duties and freight, which can add 15–25% to the factory price.

Referral Fee Rate: Enter your category's rate as a percentage. Find it in Seller Central → Fee Schedule.

FBA Fulfillment Fee: Pull the exact fee from your product's detail page in Seller Central (under "FBA Inventory" → "View Fee Preview") or from the FBA Revenue Calculator within Amazon.

Monthly Units Sold: Your target sales volume. This affects how storage cost is spread per unit — higher velocity = lower per-unit storage cost because units turn over faster.

Monthly Storage (cubic feet × months): Estimate your average inventory depth in cubic feet × months held. If you send 200 units per shipment and sell 50/week, average on-hand is ~100 units. Multiply by the product's cubic footage.

Implementation support

Turn these recommendations into a working process with Amazon Account Management.

Read the Output

The calculator shows total Amazon fees, net revenue per unit, and gross margin percentage. Focus on three numbers:

Gross Margin %: Should be your primary evaluation metric. Target 25%+ after all Amazon fees for sustainable economics. Below 20% and any cost increase (duty change, freight spike, fee increase) pushes you into unprofitability.

Break-Even ACOS: The advertising cost you can afford before erasing profit. If your margin before ads is 32%, you can spend up to 32% of your ad-attributed revenue before breaking even on those sales. This is your maximum ACOS target.

Net Profit per Unit: The absolute dollar amount you keep after all costs. At 10,000 units/month, a $2.50 vs. $3.50 net profit difference is $10,000/month — a number that changes sourcing and pricing strategy completely.

Use the Calculator for Sourcing Decisions

Before placing a purchase order with a new supplier, run the FBA fee calculator. Set your target margin (25%+) and work backward:

Maximum COGS = Selling Price × (1 − Target Margin %) − All Amazon Fees

If the supplier's price exceeds your maximum COGS, you either need a lower factory price, a higher selling price, or a lower-cost fulfillment method (FBM, 3PL). Running this math before committing to a product or supplier is how experienced Amazon sellers avoid launching unprofitable products.

Common Mistakes to Avoid

Using Amazon's built-in fee calculator as the only source: Amazon's calculator doesn't include advertising, returns, or storage costs. It shows fulfillment fees only. Always supplement it with a fully-loaded calculation.

Ignoring seasonal storage rates: Products stored in Q4 (Oct–Dec) cost 3× more per cubic foot than the rest of the year. A product with average velocity in Q4 can swing from profitable to loss-making if over-inventoried.

Not updating the model as fees change: Amazon adjusts FBA fees annually, usually in January. Rebuild your margin model each year after the fee announcement.

Forgetting returns in the margin model: A 10% return rate on a $40 product with a $4 return fee effectively adds $0.40+ per unit in cost. At scale this becomes significant.