How to calculate true FBA profitability per SKU

The gap between revenue and profit

Amazon takes money out at every stage of a sale. Referral commissions come off first, then fulfillment fees, then storage — and that is before a single cent of advertising spend. A SKU showing healthy revenue can still lose money once every cost is accounted for.

Sellers who only watch top-line sales end up scaling the wrong products: pouring inventory and ad budget into SKUs that destroy margin, while quietly profitable products go understocked. The fix is a per-SKU profit-and-loss view built from real transactions.

Every cost that eats into a sale

True profitability per SKU subtracts the full cost stack from the sale:

• Referral commission — Amazon's cut per sale, category-dependent.
• Fulfillment fee — the cost of picking, packing, and shipping.
• Monthly storage fee — charged on every unit held in FBA.
• Long-term storage / disposal fees — penalties on aged or removed stock.
• Advertising spend — what it cost to earn that attributed sale.

Why the fees are hard to see manually

The transaction data lives in Amazon's Finance reports, buried across settlement periods and fee types. Pulling it into a spreadsheet, matching it to SKUs, and attributing ad spend is days of work — and it is usually stale by the time it is done.

ReplenishIQ connects to the Amazon Finance and Ads APIs automatically and does the matching for you:

• Real financial events feed per-SKU revenue and every fee category — commission, fulfillment, storage, long-term storage, disposal.
• Ad spend is attributed to each SKU, so profitability includes what you paid to earn the sale, not just the sale itself.
• Margin and ROI are computed per SKU across selectable time windows (30/60/90 days), with clear income and cost breakdowns.
• Unprofitable SKUs are flagged automatically, so nothing hides behind a high unit count.