Margin diagnostics for Amazon FBA sellers

Find the largest fee leaking your margin, the price floor that protects it, the ACoS you can sustain, and how returns or storage shift the answer. Built on published Amazon FBA rate-card midpoints with 2026 fee-change scope reviewed — no Seller Central access required.

Amazon FBA is active. Other marketplace modules stay marked as planned until audited.

Choose the problem to diagnose

Start with the decision in front of you. Each diagnostic opens to its calculator, methodology, result interpretation, and next step.

Price the real cost of returnsreturn loss · margin drag · recovery bandOpen diagnostic →Find the largest margin leakdiscounts · processors · refunds · chargebacksOpen diagnostic →Spot inbound shipping overpayinbound freight · dimensional weight · rate varianceOpen diagnostic →Check whether a SKU still makes moneyCOGS · Amazon fees · storage residence · contribution marginOpen diagnostic →Set the ad-spend ceiling before losstrue ROAS · profit-safe CPA · break-even ceilingOpen diagnostic →Measure storage and aging pressurecapital · storage · shrinkage · aging · insuranceOpen diagnostic →

Active modelAmazon US/FBA

Other marketplace modules stay marked as planned until their own fee logic is audited.

Review date2026-05-08

Amazon fee categories are labeled modeled, included, or excluded in methodology; calculator defaults are planning midpoints, not Seller Central reconciliation.

PrivacyNo account or Seller Central access

Inputs stay private unless you choose to save an estimate.

Review methodology →