Amazon FBA Deal Validator

It calculates the referral fee as: sale price × referral fee rate. Then it adds all estimated per-unit costs (product cost + add-ons + referral fee + FBA fulfillment + monthly storage + expected returns) and computes net profit as sale price − total estimated costs. Finally, it derives profit margin (net profit ÷ sale price) and uses those results to label the deal as Accept, Caution, or Reject.

This is a simplified validator—it uses your inputs instead of category-specific Amazon fee tables, and it assumes one unit sells at the entered price. It doesn’t model ads, prep labor, packaging, taxes, reimbursements, buy box suppression, price drops, or long-term storage spikes unless you include them in add-ons. Storage and returns are treated as average per-unit estimates, so your real results can vary if your SKU’s seasonality or return behavior differs.

Make sure sale price is greater than 0 and all costs are non-negative—otherwise the calculation won’t reflect a real deal. If your referral+fulfillment costs feel “high,” check that you entered them per unit (not per shipment or per case). Also watch for unrealistic values: unusually large storage/add-ons relative to sale price will trigger warnings, since they usually indicate a units or data entry issue.

If the estimated total costs (before product cost or overall) push net profit to zero or negative, the deal is automatically flagged Reject. Profit margin calculations are based on the sale price you enter, so very small sale prices can produce misleadingly volatile margins—double-check inputs in those cases. The calculator also surfaces risk flags when return rate, storage cost, or fee load dominate the economics, even if net profit stays slightly positive.