Amazon FBA Profit, ACOS and Inventory Calculator

Model current product-level fees, expected returns, advertising and inventory turnover. Copy fee amounts from Seller Central or Amazon’s Revenue Calculator instead of relying on a short hard-coded category table.

Need the correct fulfillment input? Use the 2026 Amazon FBA fee schedule for Large Standard and Large Bulky items, then enter the rate that matches your price, size, and shipping weight.

Selling price ($)

Landed product cost ($)

Referral fee (%)

Minimum referral fee ($)

FBA fulfillment fee / unit ($)

Allocated storage / unit ($)

Inbound shipping and placement / unit ($)

Advertising cost / order ($)

Expected return rate (%)

Average net loss per returned order ($)

Other allocated costs / unit ($)

Target net margin (%)

Average units held in inventory

Expected units sold per month

Referral fee

Expected return cost / sale

Total Amazon fees entered

Net margin

ROI on landed product cost

Break-even advertising ACOS

Price needed for target margin

Months of inventory on hand

Estimated annual inventory turns

Break-even ACOS is the percentage of sale price available for ads before estimated profit reaches zero. Returns are modeled as an expected cost, not as a prediction for an individual order.

Where to get current inputs

Amazon pricing and referral-fee overview
Amazon FBA fulfillment fee documentation
Your Seller Central Revenue Calculator and business reports for product-specific fees, return rates and advertising cost.

FAQ

Why is the return rate included?
Ignoring refunds, unsellable inventory and return processing can make a low-margin product appear profitable. Use your own trailing data when available.

Is break-even ACOS the same as target ACOS?
No. Break-even ACOS consumes all modeled pre-ad profit. A sustainable target normally needs room for profit and unexpected costs.

Formula and calculation logic

Net profit = selling price − referral fee − FBA fulfillment fee − allocated storage and inbound shipping − landed product cost − advertising and other per-unit costs. Profit margin = net profit ÷ selling price × 100.

Complete worked example

At a $30 selling price, subtract a $4.50 referral fee, $4.25 fulfillment fee, $0.30 storage allocation, $0.60 inbound shipping, $8 landed cost and $3 advertising cost. Estimated profit is $9.35 and margin is 31.2%. Replace every fee with the amount for your category, size tier and current rate card.

Common mistakes

Using a referral-fee percentage from the wrong category.
Ignoring aged-inventory, returns, placement or low-inventory-level fees.
Treating sales tax collected from the buyer as seller revenue.
Using optimistic advertising cost instead of actual cost per order.

Primary sources

Related guides

Change log

July 29, 2026 — documented the complete per-unit formula, added an auditable example and separated changeable Amazon fees from seller-entered costs.