Amazon FBA Calculator

This Amazon FBA calculator models your true profitability by subtracting every Amazon fee layer — referral fees, FBA fulfillment fees, storage fees, advertising costs, and the professional seller subscription — from your selling price. Most Amazon profitability calculators only account for one or two fee lines. This one models all six, so the profit number you see is the profit you actually keep.

The referral fee is Amazon's commission on every sale, charged as a percentage of the total price (including shipping). Most categories pay 15%, but the rate ranges from 8% (Amazon device accessories) to 45% (Amazon Explore). Clothing and shoes pay 17%, jewelry pays 20%, and grocery pays 8-15% depending on price. This fee alone takes a significant chunk of your revenue before you factor in anything else.

FBA (Fulfillment by Amazon) fees cover picking, packing, shipping, customer service, and returns handling. These fees are determined by your product's size tier and shipping weight. A small standard-size item (under 1 lb) costs roughly $3.22 to fulfill, while a large standard-size item (1-2 lbs) costs around $4.75. Oversize items can cost $9-$150+ per unit. Understanding your product's size tier is critical because even small dimensional changes can push you into a higher fee bracket.

Storage fees are the silent profit killer. Monthly storage runs $0.87 per cubic foot from January through September and jumps to $2.40 per cubic foot during Q4 (October-December). More importantly, inventory aged over 181 days incurs an additional surcharge of $1.50-$6.90 per cubic foot. Products that sit too long in Amazon warehouses can actually cost you money to store. On top of everything, most competitive categories require PPC advertising to maintain visibility, with average ACoS (Advertising Cost of Sale) running 15-30%.

Use your calculated profit margin to set a break-even ACoS for advertising. If your margin before ads is 30%, any campaign with ACoS under 30% is profitable. Start PPC campaigns with automatic targeting to discover converting keywords, then move top performers to manual campaigns with tighter bids. Most successful Amazon sellers spend 10-15% of revenue on advertising while maintaining 15-25% net profit.

Optimize your product dimensions and packaging to stay within the lowest possible FBA size tier. Even reducing package dimensions by half an inch can drop your fulfillment fee by $1-2 per unit. Work with your supplier to design packaging that minimizes void space. For products near a size-tier boundary, this single optimization can increase profit margin by 3-5 percentage points.

Monitor your inventory health weekly using Amazon's Inventory Performance Dashboard. Maintain 30-60 days of inventory to balance stockout risk against storage costs. Set up automated repricing rules to accelerate sales on slow-moving inventory before it crosses the 181-day threshold. Products approaching the aged inventory surcharge deadline should be discounted, bundled, or removed rather than stored at a loss.