Net profit = price minus every fee minus item cost. That is the whole idea; the 2026 version of the list is what separates a real estimate from a flattering one. Here is the formula, then a $30 unit walked through it.
Net profit = Price − Referral − Fulfillment − Fuel surcharge − Ads − Freight − Storage − Returns − Placement − Item cost
Net margin = Net profit ÷ Price × 100
The list looks long because the fees are long — but notice who sets each line. Referral and fulfillment come off Amazon's schedule; ads and freight come out of your decisions; returns, storage and placement come out of your inventory discipline. The formula exists so you can see which lever you actually control.
| Step | Amount |
|---|---|
| Selling price | $30.00 |
| Referral (15%) | −$4.50 |
| Fulfillment (large-standard band) | −$4.20 |
| Fuel surcharge (3.5%) | −$0.15 |
| Advertising (10%) | −$3.00 |
| Inbound freight ($300 ÷ 200 units) | −$1.50 |
| Returns amortized (category rate) | −$1.35 |
| Storage (~60 days) | −$0.04 |
| Placement fee | −$0.30 |
| Item cost | −$8.00 |
| Net profit / margin | $6.96 / 23.2% |
The same run produces the break-even price — $20.57 on this example — so you see your pricing floor next to your margin. Re-calculate after every published fee change; the Jan 15 and Apr 17 2026 moves shifted floors across the whole catalog.
Then check one number against Seller Central: pull a recent order's fee preview and compare its lines to your last estimate. They should match within a few cents. Where they diverge, your model has a wrong bucket — and the formula above shows you exactly which row to fix.
Enter price, cost, category and dimensions — the calculator applies the full 2026 rate card and shows the same line-item breakdown:
Net profit per unit = selling price − referral fee − fulfillment fee − fuel surcharge − advertising − inbound freight − storage − return amortization − placement fee − item cost. On a typical $30 home product that nets $6.96, a 23.2% margin. The five buckets most free calculators forget are freight, storage, returns, placement and fuel.