Amazon FBA Fee Calculator

Referral fee = Selling price × Category rate
Dimensional weight = (L × W × H) / Divisor
Billable weight = max(Unit weight, Dimensional weight)
Fulfilment fee = tier rate for that size band and billable weight
Storage = (L × W × H / 1728) × Monthly rate per cubic foot
Net profit = Price − Product cost − Referral − Fulfilment − Storage

• Category ratereferral percentage Amazon sets per category, commonly 8% to 15%
• Billable weightthe greater of actual and dimensional weight, which is what the fee tier reads
• Divisordimensional weight divisor, 139 for US cubic-inch measurements
• Product costlanded cost per unit: manufacturing plus freight plus duty

• Fee schedules are Amazon policy, not arithmetic. Referral percentages, size-tier boundaries, and per-pound rates are revised on a published date each year and differ by marketplace, so treat any figure here as the shape of the calculation rather than a permanent number, and check Seller Central before pricing.
• Dimensional weight beats actual weight for anything light and bulky. A pillow can sit two tiers above its scale weight, which is why shaving half an inch off box height sometimes moves more profit than renegotiating unit cost.
• Storage is the fee sellers most often ignore, and it is the one that compounds. Long-term storage surcharges and low-inventory or aged-inventory fees apply to units sitting past their thresholds, and slow movers can quietly consume their own margin.
• Returns are not free even when the customer pays nothing. You keep the referral fee refund but lose the fulfilment fee on most categories, plus return processing, so a 10% return rate hits a thin-margin item far harder than the headline number suggests.