Enter your selling price, product cost, shipping, and the Amazon fees for your product (referral %, FBA fulfillment fee, optional storage). You'll get net profit per unit, profit margin, and ROI with every fee itemized.
How FBA profit works
When you sell through Fulfillment by Amazon, two fees come off the top of every sale: a referral fee (a percentage of the selling price, 15% for most categories) and an FBA fulfillment fee (a flat per-unit charge based on the item's size tier and weight). Add your own costs — buying the product, shipping it to Amazon's warehouse, storage, and anything else — and what's left is your actual profit per unit. Sellers routinely price off the referral fee alone and then wonder where the money went.
One honest caveat: Amazon's exact fees live in the rate cards in Seller Central and depend on your product's size tier, weight, and category. This calculator computes profit from the fees you enter — look yours up first, then the math here is exact.
The formula
Profit = Price − Product cost − Shipping − (Price × Referral %) − Fulfillment − Storage − Other
Price is your selling price; referral % is charged on that price, not on your cost. Margin is profit ÷ price, and ROI is profit ÷ (product cost + shipping) — the return on the cash you actually put in.
Worked example
You sell an item for $24.99. It costs $6.00 to make, $1.50 to ship to Amazon, the referral fee is 15% ($3.75), fulfillment is $3.50, and storage runs $0.30 per unit-month.
Profit = 24.99 − 6.00 − 1.50 − 3.75 − 3.50 − 0.30 = $9.94 per unit — a 39.78% margin and a 132.55% ROI on your $7.50 of invested cash.
The rule of 3 (and the Q4 storage trap)
A quick sanity check experienced sellers use: a healthy FBA product splits the selling price into roughly thirds — ⅓ product cost, ⅓ Amazon fees, ⅓ profit. If your fees are eating half the price, the product is too cheap or too heavy for FBA. Also watch the calendar: Amazon's monthly storage rates roughly triple from October through December, so slow-moving inventory that was quietly profitable all year can turn into a storage bill during Q4. Run your numbers with the seasonal rate before sending in a holiday-sized shipment.
Frequently asked questions
What is a good profit margin for Amazon FBA?
Most experienced sellers aim for a net margin of 20% or more after all fees and costs. Between 10% and 20% is workable but leaves little room for ad spend or returns, and under 10% usually means one fee increase or price war away from losing money.
How do I find my exact Amazon fees?
In Seller Central: referral fees depend on your category (15% for most), and FBA fulfillment fees depend on your product's size tier and weight — both are published in Amazon's rate cards. This calculator uses the fees you enter, so look yours up there first and the result will match reality.
What is the FBA rule of 3?
A quick screening heuristic: a healthy FBA product splits its selling price into roughly thirds — one third product cost, one third Amazon fees, one third profit. If Amazon's cut is approaching half the price, the item is likely too cheap, too heavy, or too bulky to work on FBA.
Does this calculator include advertising (PPC) costs?
Not automatically — put your average per-unit ad spend in the "Other costs" field. Dividing your monthly PPC budget by monthly units sold gives a reasonable per-unit figure, and it often turns a paper profit into a much thinner real one.
Why are Amazon storage fees higher in Q4?
Amazon's monthly storage rates roughly triple from October through December to ration warehouse space during the holiday rush. Slow-moving inventory that costs pennies to store in July can rack up meaningful fees in November, so re-run your numbers with the seasonal rate before a big Q4 shipment.