FBA profit calculator
An FBA profit calculator works out what you actually keep from each Amazon sale: it takes the selling price, subtracts your landed product cost, Amazon’s referral fee, the FBA fulfilment fee and any storage and advertising costs, and returns net profit per unit, margin, ROI and break-even ACoS. Free and no sign-up. Dropshippers can use it too, by zeroing the FBA fee.
Your numbers
Per-unit result
- Amazon fees per unitReferral + fulfilment + storage—
- Profit per unit before ads—
- Net profit per unit—
- Net margin—
- ROI on product costNet profit ÷ landed cost—
- Break-even ACoSThe ACoS at which an ad-driven sale makes zero profit—
Results are computed only from the numbers you enter. Fees vary by category, size and weight, so check your product’s actual rates in Seller Central.
LumaiScope’s full calculator pulls measured price, BSR and fee data for a real ASIN and turns it into a GO / WATCH / NO-GO verdict. Try it free.
How the maths works
- Amazon fees per unit = referral fee (price × your category’s rate) + FBA fulfilment fee + storage per unit.
- Profit before ads = selling price − landed cost − Amazon fees.
- Net profit = profit before ads − ad spend per unit sold.
- Net margin = net profit ÷ selling price. ROI = net profit ÷ landed cost.
- Break-even ACoS = profit before ads ÷ selling price. Bids that keep ACoS below this number make money on every attributed sale.
The two mistakes this catches most often: margins computed from the factory price instead of the landed cost, and forgetting the referral fee, which often rivals the product cost itself. For the full method, read the guide on calculating profit margins for FBA and dropshipping.
Frequently asked questions
Which costs does this calculator include?
The selling price, your landed product cost, Amazon's referral fee, the FBA fulfilment fee, and optional per-unit storage and advertising costs. Every figure is one you enter yourself, so nothing is estimated behind your back.
Where do I find my FBA fulfilment fee and referral fee?
Both live in Seller Central: the fee preview on any listing shows the exact fulfilment fee, and Amazon publishes the referral-fee schedule by category. The referral fee is 15% in many categories, but check yours, since some categories differ a lot.
What is break-even ACoS and why does it matter?
Break-even ACoS is the advertising cost of sale at which an ad-driven sale makes zero profit. It equals your profit margin before ad spend. Campaigns running below it make money on every attributed sale; campaigns above it are buying sales at a loss.
Can I use this for dropshipping?
Yes. Set the FBA fulfilment fee to zero, put your supplier's shipping cost inside the landed product cost, and set the referral fee to whatever your platform charges. For most dropshipping stores the ad spend per order is the number that decides the margin.
How is this different from the calculator inside LumaiScope?
This page computes from numbers you type in. The in-app Calculator looks up a real ASIN, pulls measured price, BSR and fee data, runs the same maths on it, and ends in a GO / WATCH / NO-GO verdict with the reasoning shown.
Run it on a real product
Paste an ASIN and LumaiScope pulls the measured price, BSR and fees, runs the same maths, and ends in a plain-English GO / WATCH / NO-GO verdict. Start free, no credit card.
Start free