Amazon FBA Fee Profit Calculator
Open one FBA unit like a carton: selling price on top, then referral, fulfillment, storage, inbound, product, prep, return, advertising, other, and monthly-plan allocation. See contribution profit per unit, monthly profit, margin, cost ROI, break-even price, and maximum advertising rate.
Pack the per-unit profit carton
Expected units are retained, paid units for allocating monthly cost. If the sales plan charges per item instead of monthly, add that amount to other variable cost. Return allowance represents the expected economic loss after refunds, recovery, removal, disposal, and fee credits; reconcile it with real return reports rather than using a universal percentage.
FBA carton formulas
Referral fee = selling price × entered category referral rate
Monthly allocation per unit = monthly plan and tools ÷ retained monthly units
Return and ad allowances = selling price × entered rates
Per-unit profit = price − every entered per-unit fee, inventory cost, allowance, and allocation
Break-even price = fixed-dollar unit costs ÷ [1 − referral rate − return rate − ad rate]
Maximum ad rate = contribution before ads ÷ selling price
“Fixed-dollar unit costs” means costs entered as dollars per unit plus the monthly allocation, not business fixed cost in an accounting sense. The formula assumes percentage costs continue to scale with price. A category fee with a minimum, tier, or price breakpoint must be modeled from the current Amazon schedule instead of forcing one rate across all prices.
Worked $39.99 standard-size example
The default unit sells for $39.99. A fifteen-percent referral rate costs $6.00 after rounding. Entered FBA fulfillment is $4.15. Storage, inbound placement or freight, and the $39.99 monthly plan allocated over 500 retained units total about $1.03. Landed inventory and prep cost $9.50.
A three-percent return allowance is $1.20 and an eighteen-percent ad allowance is $7.20. Adding $0.25 other variable cost produces $29.33 total modeled cost and $10.66 contribution profit. Margin is 26.67 percent of price; profit is 36.36 percent of modeled cost. At 500 retained monthly units, modeled contribution is $5,331.81. Holding percentage costs constant, the break-even price is $23.33 and the maximum ad rate is 44.67 percent.
Start with Amazon’s current fee data, not a remembered table
Referral
Amazon states that referral fees generally use a category percentage of total sales price or a category minimum, whichever is greater. Tiered categories and low-price exceptions require their exact current rule.
Fulfillment
FBA fulfillment varies with size tier, shipping weight, dimensions, apparel status, price programs, and other classification. A packaging change can move a unit across a fee boundary.
Inventory services
Monthly storage uses daily average volume and season. Inbound placement, aged inventory, removal, disposal, low inventory, prep, labeling, and optional services can create separate costs.
Amazon’s 2026 notice says U.S. FBA fees rose by an average of $0.08 per unit and introduced no new FBA fee types, with changes generally effective January 15, 2026. An average change is not a SKU quote. Export Fee Preview and inspect the exact ASIN.
Measure the packaged unit that Amazon receives
A product can be light but dimensionally expensive. Amazon explains that fulfillment costs depend on weights, dimensions, and size tier, and shipping weight can use unit or dimensional weight under applicable rules. Measure the fully packaged sellable unit, including protective materials, polybag, box, inserts, and bundled components.
Audit catalog dimensions after packaging changes and keep photographs, scale readings, and ruler measurements. If Amazon measures differently, follow the current remeasurement process. A one-inch or few-ounce difference can move the fee far more than a small sourcing discount.
Convert storage from inventory-month to sold-unit economics
Storage is charged on inventory present, not only units sold. Dividing one month’s storage charge by that month’s retained sales can be useful, but it rises when inventory turns slowly and can look artificially low when a stockout boosts sell-through. Use a multi-month cohort or forward inventory plan.
Include seasonal rates, aged-inventory exposure, damaged and stranded units, removal or disposal, and storage before launch. The $0.15 default is an input example, not an Amazon rate. Run slow, base, and fast inventory turns.
Inbound cost begins at the supplier door
Landed cost can include manufacturing, inspection, packaging, duty, tariff, brokerage, international freight, insurance, drayage, domestic freight, and receiving. Then allocate shipment-to-Amazon freight and any inbound placement service fee. Avoid hiding placement cost inside COGS in one SKU and inbound in another if the goal is comparison.
Choose an allocation driver that reflects cartons, cubic volume, weight, units, or shipment charges. Reconcile the shipment plan actually selected; Amazon can offer different inbound placement options and costs.
Model return loss, not only return count
A returned unit may be resellable, discounted, damaged, lost, removed, disposed, or refunded without return. Referral and fulfillment fee treatment, return processing, customer reimbursement, inventory adjustment, and recovery differ. The economic loss per return can exceed or fall below price.
Calculate a cohort’s net return loss divided by original units, then express that as dollars or percent of sales for this input. Separate product defect, listing mismatch, size/fit, damage, and buyer-remorse causes so operational fixes are visible.
Advertising rate must match attributed sales scope
Amazon advertisers often use ad cost of sales, but ad-attributed sales and total sales are different denominators. The calculator’s ad percentage applies to every modeled unit’s selling price, which is appropriate only when the entered rate represents blended advertising spend divided by the same retained sales scope.
For a launch, include coupon, promotion, Vine, creative, and external traffic costs when they are incremental. Test higher ad rate because bids and conversion can deteriorate as spend scales. The maximum rate is mathematical, not a recommended target; zero profit leaves no return for risk, overhead, or tax.
Contribution profit is not final business net income
The monthly plan allocation can include the Professional plan and directly shared tools, but a business also has staff, owner labor, software, accounting, legal, insurance, warehouse, financing, samples, travel, office, product development, and tax. Add truly variable items here; subtract broader fixed overhead in a portfolio profit-and-loss statement.
A SKU can have positive contribution yet fail to cover its fair overhead share. Conversely, a low-volume SKU can appear unprofitable when an entire monthly plan is assigned to it. Use a consistent allocation and review both unit contribution and company profit.
Compare FBA and merchant fulfillment with complete cost
Amazon offers tools to compare FBA with your fulfillment. For merchant fulfillment, include pick labor, packaging, carrier zone and surcharge, delivery loss, customer service, returns, warehouse, software, and service-level impact. For FBA, include inbound, inventory carrying, placement, storage, and program fees.
Use the same selling price, return behavior, conversion, delivery promise, and labor value. A fulfillment method is not “cheaper” if the comparison omits the seller’s own labor or uses a promotional carrier quote that does not match the parcel.
Monthly settlement audit
SKU evidence
Save category, price, dimensions, weight, size tier, Fee Preview, inventory age, ad report, landed-cost sheet, and return disposition.
Cash evidence
Reconcile orders, refunds, reimbursements, fees, reserves, adjustments, ad billing, disbursement, bank deposit, and inventory ledger.
Compare expected and actual fee per unit. Investigate catalog changes, measurement, price tier, season, service, return, and allocation before changing price. Do not rely on a single settlement line without the transaction detail.
Sales tax collection and income tax are separate
Marketplace-facilitator rules, Amazon tax calculation, customer tax, business gross receipts, inventory capitalization, cost of goods sold, advertising, fees, refunds, and state filings follow different rules. Customer sales tax collected and remitted by a marketplace is not a profit component merely because it appears in transaction data.
IRS Publication 334 explains gross receipts, returns and allowances, cost of goods sold, and ordinary and necessary business expenses for qualifying small businesses.
Frequently asked questions
Does the calculator know my 2026 fulfillment fee?
No. Enter the current SKU-specific amount from Amazon’s tools and verify dimensions, weight, tier, and eligibility.
Should sales tax be included in selling price?
Use the referral-fee base and revenue treatment applicable to the transaction. Do not treat marketplace-remitted customer tax as profit.
Why allocate the monthly plan?
It prevents a recurring account cost from disappearing. Use a portfolio allocation when multiple SKUs share it.
Is maximum ad rate a good target?
No. It is the modeled zero-profit ceiling under unchanged assumptions, leaving nothing for broader overhead, risk, or tax.
Is per-unit contribution my taxable profit?
No. Tax books use actual revenue, inventory, refunds, expenses, entity rules, and filing guidance.
Separate marketplace revenue from fulfillment costs by estimating the top line first with the Amazon sales calculator.