Referral fee and its minimum
The referral fee is usually a percentage of the selling price, but Amazon applies a minimum fee per unit. At a low price, the minimum can be a larger share of the sale than the percentage.
This calculator takes the greater of price × referral % and the minimum. Change both fields if your category or marketplace differs.
FBA fulfillment versus FBM shipping
FBA replaces your shipping cost with Amazon's fulfillment fee, then adds storage, inbound and potential removal. FBM uses your own shipping and packing cost and does not pay FBA storage.
Switch the fulfillment method to see the same unit under both models. The detailed FBA-vs-FBM comparison lives in the related calculator.
Storage is a function of time
Storage is cubic feet × months × the seasonal rate. Standard-size units pay more per cubic foot in October–December than in January–September, and bulky units have a different rate.
The storage table shows 1, 3 and 6 months. A unit that sells quickly carries little storage; slow inventory can erase the margin.
Worked example
FBA, price $29.99, unit cost $7, referral 15% with a $0.30 minimum, FBA fulfillment $5.50, storage 0.15 ft³ for 3 months at $0.78, inbound $0.60, removal $0.
Referral is $4.50, storage $0.35, total fees $10.95 and net profit $12.04. Net margin is 40.15% and the fee take rate is 36.51%.
Inbound and removal are easy to forget
Inbound freight and prep are paid before the unit sells. Removal fees appear when inventory is sent back or destroyed. Both reduce the unit economics even though neither is a referral or fulfillment fee.
Enter them per unit. If you do not remove inventory, keep removal at 0; the field is there for the units that do.
Where the model stops
It excludes advertising, taxes, returns, aged-inventory surcharges, multi-unit orders, dimensional-weight surprises and currency conversion. It also uses editable fee estimates, not a live Amazon quote.
Confirm the referral category and FBA fee in Seller Central before setting a price. Use the FBA-vs-FBM page when the decision is which fulfillment method to use.