Fee Assumptions & Methodology
Results are based on your inputs and stated assumptions — not live Amazon Seller Central data.
Our Approach
FBA Profit Engine uses an assisted fee model. Unlike other tools that claim to pull live Amazon data, we believe in transparency and accuracy through manual inputs.
You provide the fee values (which you can get from Amazon's Revenue Calculator), and we calculate profit scenarios consistently and reliably. This approach eliminates the risk of outdated automation and gives you full control over your assumptions.
Fee Components Explained
Referral Fee
Amazon's commission on each sale, typically ranging from 8% to 45% depending on the category.
Default: 15% (most common)
How to find yours: Check your category's referral fee in Amazon Seller Central → Pricing
FBA Fulfillment Fee
Amazon's fee for picking, packing, and shipping your product. Varies by size and weight.
Estimated tiers:
- Small Standard (10 oz or less): $3.22
- Large Standard (1-2 lbs): $4.75
- Large Standard (2-3 lbs): $5.40
- Oversize (estimate): $8.00
How to find yours: Use Amazon's Revenue Calculator for exact fees
Inbound Shipping
Cost to ship your products from supplier to Amazon warehouse. Calculate this per unit based on your shipping quotes and order quantities.
Prep & Packaging
Any prep costs required (labeling, polybagging, bundling). Include Amazon's prep fees if you use their prep service.
Advertising (PPC)
You can enter advertising cost in two ways:
- Per-unit cost ($): If you know your average ad spend per unit sold
- TACoS (%): Total Advertising Cost of Sales as a percentage of revenue
Storage Fees
Monthly storage fees divided by expected monthly sales. More relevant for slow-moving inventory.
Returns Rate
Percentage of orders that result in returns. The calculator accounts for lost profit on returned units.
How We Calculate
Net Profit per Unit
Sale Price - (COGS + Referral Fee + Fulfillment Fee + Inbound Shipping + Prep + Ads + Storage + Returns Cost)Net Margin %
(Net Profit / Sale Price) × 100ROI %
(Net Profit / COGS) × 100Breakeven Price
Fixed Costs / (1 - Variable Cost %)The minimum sale price needed to hit $0 profit
Assumptions Versioning
Every calculation is stored with an assumptions version number (v1.0). This ensures transparency and allows you to track how assumptions may have changed over time.
All saved scenarios include the version used at the time of calculation, providing a complete audit trail for your decision-making.
Important Notes
- •Referral fees vary by category (8%-45%). Default is 15%.
- •Fulfillment fees are estimates and vary by size/weight.
- •Users must input actual fees from Amazon's fee calculator for accuracy.
- •This is an assisted fee model, not automated Amazon data sync.