How This Calculator Works
The FBA Profit Calculator computes your true profit per unit by subtracting every cost layer from your sale price. It starts with your product cost (COGS), then adds Amazon's referral fee (a category-specific percentage of the sale price), the FBA fulfillment fee (based on your product's size tier and weight), monthly storage costs, PPC advertising spend, estimated return losses, and any additional prep or inspection fees.
FBA fulfillment fees are calculated using Amazon's 2026 fee schedule with nine size tiers ranging from Small Standard to Large Oversize. The calculator auto-selects the fee based on your chosen tier and weight, including the per-pound surcharge for heavier items. The referral fee updates dynamically when you change the product category, with rates from 8% (Consumer Electronics) to 45% (Amazon Media).
The results include a visual bar chart showing where every dollar of your sale price goes, a detailed line-item cost breakdown with percentages, and a projections table that scales your unit economics to per-shipment, monthly, and annual figures. The ROI metric shows profit divided by COGS, giving you a clear picture of return on your sourcing investment.
Example Scenario
You source a Home & Kitchen product for $6.50 per unit and ship it to FBA for $1.50 per unit. Your sale price is $29.99. The product is Large Standard (under 1 lb), so the FBA fulfillment fee is $4.09. The referral fee at 15% is $4.50. Monthly storage is $0.15 per unit, PPC costs $2.00 per unit, and your 3% return rate adds about $0.45 in return cost per unit.
Total costs: $6.50 + $1.50 + $4.50 + $4.09 + $0.15 + $2.00 + $0.45 = $19.19. Your profit per unit is $29.99 - $19.19 = $10.80, a 36% margin. Your ROI on COGS is 166% ($10.80 / $6.50). Amazon takes $8.74 per unit (referral + FBA + storage), which is 29.1% of your sale price.
If you ship 500 units per month, your monthly profit is $5,400 and your annual profit projection is $64,800. The break-even point for your initial shipment investment of $4,000 is just 370 units.
When to Use This Tool
Use this calculator during product research before you commit to sourcing a new item. Plug in your supplier quote, estimated sale price, and the correct category and size tier to see whether the margins support a viable FBA business. If the margin falls below 20%, the product may not survive PPC cost increases or fee changes.
This tool is also essential when evaluating price changes. If a competitor undercuts you and you need to lower your sale price, run the new number through the calculator to see how it affects your per-unit profit, margin, and ROI. You can also use it to compare different fulfillment size tiers and figure out whether downsizing your packaging could save you money on FBA fees.
Frequently Asked Questions
What margin should I target for FBA products?
Most successful FBA sellers target a minimum of 25% to 30% net margin after all costs. Below 20%, there is very little room for error. A single fee increase, a PPC cost spike, or an uptick in returns can wipe out your profit entirely. Higher-margin products (35%+) give you more flexibility to invest in advertising and absorb seasonal fee changes.
How do I find my product's FBA size tier?
Amazon classifies products by their packaged dimensions and weight. Small Standard items must be under 15" x 12" x 0.75" and under 12 oz. Large Standard items can be up to 18" x 14" x 8" and up to 20 lbs. Anything larger falls into Oversize tiers. You can find your exact tier in Amazon Seller Central under the FBA Revenue Calculator, or measure your packaged product and compare against the published size tier chart.
Are storage fees really only $0.15 per unit?
The $0.15 default is an average estimate for standard-size items during non-peak months (January through September). Storage fees are charged per cubic foot, so larger items cost more. During Q4 (October through December), storage fees can increase 2x to 3x. If your inventory sits in Amazon's warehouse for over 365 days, you also face aged inventory surcharges. Plan to turn inventory within 60 to 90 days to keep storage costs minimal.
Why is PPC cost included in the profit calculation?
On Amazon, advertising is not optional for most products. New listings need PPC to generate initial sales velocity and reviews. Even established listings typically spend $1 to $5 per unit on advertising to maintain visibility. Excluding PPC from your profit calculation gives you an inflated margin that does not reflect real-world economics. The average FBA seller spends 10% to 15% of revenue on PPC.
How often does Amazon change FBA fees?
Amazon typically announces annual fee changes in late Q4 or early Q1, effective from January or February. Fees have generally trended upward year over year. This calculator uses the 2026 published fee schedule. We recommend checking this page periodically for updates, and always cross-referencing with Amazon Seller Central before making large sourcing commitments.