How to Calculate Amazon FBA Profit
Amazon FBA profitability is more than selling price minus product cost. A useful estimate accounts for marketplace fees, fulfillment, inbound freight, advertising, returns, and other costs that reduce what you keep. This guide shows a practical per-unit formula, a worked example, and the metrics to review before making inventory or pricing decisions.
Last reviewed: 2026-09-04
Amazon FBA profit formula
A practical per-unit profit calculation starts with the revenue from one sale and subtracts every cost that can reasonably be allocated to that unit.
- FBA Profit per Unit = Selling Price − Product Cost − Amazon Fees − Fulfillment Costs − Inbound Shipping − Advertising − Other Variable Costs
For a fast scenario estimate, use the Amazon FBA Calculator. Always verify actual Amazon fees against current marketplace fee schedules before making purchasing decisions.
Amazon FBA profit example
Suppose a product sells for $40. Your landed product cost is $12 per unit, Amazon-related fees and fulfillment total $11, allocated advertising cost is $4, and other variable costs are $1.
- Profit = $40 − $12 − $11 − $4 − $1
- Profit = $12 per unit
If you sell 500 units under the same assumptions, estimated contribution from those units is $6,000 before any fixed overhead or taxes that are not included in the per-unit calculation.
How to calculate FBA profit margin
Profit dollars tell you how much a unit contributes. Profit margin expresses that profit as a percentage of sales revenue.
- Profit Margin = Profit per Unit ÷ Selling Price × 100
- $12 ÷ $40 × 100 = 30%
In this example, the estimated per-unit profit margin is 30%. You can test other scenarios with the Profit Margin Calculator and read our guide to calculating profit margin.
Costs to include in an FBA profitability estimate
The quality of your result depends on the quality of your inputs. Depending on your product and marketplace, relevant costs can include:
- Product cost: the amount paid to manufacture or purchase the item.
- Inbound freight and duties: shipping, customs, prep, labeling, or related costs allocated to each unit.
- Amazon fees: applicable referral, fulfillment, storage, or other marketplace charges.
- Advertising: attributable sponsored-ad cost or another reasonable per-unit acquisition estimate.
- Returns and refunds: expected losses that materially affect unit economics.
- Other variable costs: packaging, inspection, third-party services, or costs that increase with sales volume.
Do not assume a fee percentage from an old example is still valid. Marketplace fees and policies can change, and product dimensions or category can materially affect the result.
Revenue is not profit
A listing generating $20,000 in monthly sales is not necessarily more attractive than one generating $10,000. The first product may have higher product costs, fees, advertising costs, or return rates. Compare net economics rather than revenue alone.
This distinction becomes especially important when discounts increase sales volume but compress the amount earned on each unit.
FBA profit margin vs ROI
Profit margin and ROI use different denominators. Margin compares profit with revenue, while ROI compares a return with the investment used to generate it. A product can have a reasonable margin but tie up substantial cash in inventory for a long period.
Use the ROI Calculator and our ROI calculation guide when you want to evaluate return relative to invested capital.
How advertising changes FBA profitability
Advertising can increase sales while reducing per-unit profit. If a $40 product has $16 of profit before advertising and attributable ad cost averages $4 per sale, profit after that advertising allocation falls to $12.
When evaluating campaigns separately, ROAS can help compare attributed advertising revenue with ad spend. However, ROAS is not the same as product profit because it does not by itself deduct product cost, marketplace fees, fulfillment, or overhead.
Calculate your break-even selling price
If total variable cost per unit is $28, a $28 selling price would leave zero contribution before fixed costs under those assumptions. In practice, a sustainable price needs room for profit, fixed overhead, unexpected costs, and any taxes that apply to the business.
Use the Break-Even Calculator for broader business scenarios involving fixed costs and contribution margin.
Run sensitivity scenarios before ordering inventory
Do not evaluate only one best-case estimate. Test what happens if selling price falls, advertising cost rises, freight increases, or return rates worsen. A simple downside scenario can reveal whether a product remains viable when conditions are less favorable.
For example, reducing the $40 selling price in our example to $36 while keeping the same $28 total variable cost would reduce profit from $12 to $8 and margin from 30% to about 22.2%.
Common Amazon FBA profit calculation mistakes
- Ignoring inbound freight. Supplier price is not always the full landed product cost.
- Using outdated marketplace fees. Verify current fees for your product, dimensions, category, and marketplace.
- Leaving out advertising. Paid acquisition can materially change unit economics.
- Confusing revenue with profit. Sales volume does not show what remains after costs.
- Ignoring returns and other leakage. Small recurring costs can become significant at scale.
- Using margin and ROI interchangeably. They answer different financial questions.
Use estimates as a decision tool, not a guarantee
An FBA profitability calculation is a model based on assumptions. Actual results can change with fees, selling price, advertising performance, inventory age, storage, freight, exchange rates, returns, and other operating conditions. Update your inputs with actual data regularly and compare estimated profit with realized profit.