Inputs to review
- Amazon listing price and visible product details
- Supplier pack cost, pack match, and MOQ
- Shipping, ads, returns, discounts, and fee assumptions
- Storage rate and expected inventory hold period
What the estimate shows
- Estimated profit, margin, and ROI per unit
- Break-even price and maximum supplier buy price
- Fee-input confidence, decision status, and diagnostic reasons
- Price-drop, supplier-cost, and available ad-scenario comparisons
What the estimate should include
A useful FBA estimate starts with the listing price, then accounts for the costs that reduce proceeds: marketplace referral and fulfillment fees, supplier cost, inbound shipping, advertising, discounts, and expected return-related costs.
Fulfillment estimates can depend on product details and size tier. Check the listing data and assumptions before relying on a result, especially when dimensions or shipping weight are uncertain.
- Treat estimated fees as planning inputs, not an official Amazon fee quote.
- Use the same cost basis when comparing products.
Read the buy signal in context
The Buy, Review, or Avoid recommendation summarizes the configured thresholds and current estimate. The result also surfaces fee-input confidence and diagnostic reasons; confidence is not a prediction of sales or profit.
Use Review when a key input needs confirmation. A small change in supplier cost, fees, or selling price can move the result. Check pack matching and seller-confirmed eligibility before treating a positive calculation as a Buy.
Using an FBA calculator before you buy
An FBA profit calculator is most useful before purchase, when you can still walk away. Enter the real selling price you expect to hold, your landed supplier cost, and the packed size and weight.
Compare the result with a lower-price scenario. If the product only works at the best recent price, treat it as a Review item instead of a Buy.
Check the assumptions that move an FBA estimate
Reconcile the estimate on a per-listing-unit basis: expected selling proceeds after discounts, minus the supplier cost and the marketplace, fulfillment, inbound, storage, advertising, and return assumptions that apply to that unit. Keep each amount tied to the same pack size so a case price is not compared with a single-unit sale.
Before relying on a positive result, verify the exact variation, category, fulfillment eligibility, package dimensions, and shipping weight. If a fee-driving measurement or classification is uncertain, enter a verified value or leave the decision at Review rather than guessing.
- Measure the packaged item and compare it with the listing data before accepting a size-tier estimate.
- Run a lower-price scenario and compare the resulting profit with your minimum return threshold.
- Confirm whether prep, inbound placement, storage time, and return processing belong in your cost basis.
Common questions
Frequently asked questions
Does the calculator guarantee my Amazon profit?
No. It estimates unit economics from listing details and the assumptions entered. Actual fees, returns, advertising, sale price, and other costs can differ.
Do I need to connect Seller Central?
No Seller Central connection is required. Margin Seller reads supported details visible on the product page and lets you enter your own costs.
How do I calculate Amazon FBA profit?
Subtract every per-unit cost from the selling price: supplier cost, referral fee, fulfillment fee, storage, returns, prep, inbound shipping, and advertising. Margin Seller does this from the visible listing and your own inputs.
What is a good ROI for Amazon FBA?
There is no universal number. Many sellers set a minimum profit in dollars and a minimum ROI percentage, then require both. Set yours from your capital, risk tolerance, and how quickly the product sells.
Ready to check a listing?
Put the assumptions to work.
Bring the visible listing facts and your own costs into a product audit before you commit to inventory.