The single formula that matters, in order:
Net profit = Price − Referral fee − Fulfillment fee − Fuel surcharge − Advertising − Inbound freight − Storage − Return amortization − Item / landed cost
Net margin = Net profit ÷ Price × 100
The five cost buckets most free calculators forget are inbound freight, storage, returns, placement and fuel. If a calculator only shows referral + fulfillment, it is a fee calculator, not a profit calculator — and it will flatter your margin by 3–8 points on slow-moving or heavy products.
| Fee | How it's charged (US, 2026) | Typical share of price |
|---|---|---|
| Referral fee | % of price by category — 8% electronics, 15% most categories, tiered (beauty 8% ≤ $10 then 15%) | 8–15% |
| Fulfillment fee | small-standard tiers + 12 large-standard bands, dimensional weight (divisor 139 in/lb), 3–20 lb per-4-oz formula | $3.20–$6.50 typical |
| Fuel & logistics surcharge | 3.5% of fulfillment fee, from Apr 17, 2026 | ~0.5–0.7% |
| Advertising | your PPC spend, usually 10–30% of revenue by category | 10–30% |
| Inbound freight | your shipping + customs per unit (total shipment ÷ units) | $0.50–$3.00 |
| Monthly storage | $0.78/ft³ off-peak, $2.40/ft³ Oct–Dec (standard size) | $0.02–$0.30 on slow movers |
| Returns | referral + fulfillment + processing fee on each returned unit | 1–3 points of margin |
A 10 oz product sized 6 × 4 × 2 in (large standard-size), home category, $30 selling price, $8 landed cost, 10% ad spend: ⚡ Try this case live
| Line item | Amount | % of price |
|---|---|---|
| Referral fee (15%) | $4.50 | 15.0% |
| FBA fulfillment (2026 large standard) | $4.20 | 14.0% |
| Fuel & logistics surcharge (3.5%) | $0.15 | 0.5% |
| Advertising (10%) | $3.00 | 10.0% |
| Inbound freight ($300 / 200 units) | $1.50 | 5.0% |
| Return amortization (8%) | $1.35 | 4.5% |
| Storage (60 days) | $0.04 | 0.1% |
| Inbound placement (minimal split) | $0.30 | 1.0% |
| Total fees | $15.04 | 50.1% |
| Item / landed cost | $8.00 | 26.7% |
| Net profit | $6.96 | 23.2% margin |
The break-even price here is $20.57 — drop below it and every sale loses money. The exact numbers change with your category, dimensions and ad spend; the calculator below reproduces this example with one click.
These five are the margin-killers this page models directly; the other three — freight treatment, returns amortization and placement splits — are dissected in 6 FBA profit calculation mistakes new sellers make.
Run the worked example above instantly — every parameter is pre-filled:
Open the FBA Profit Calculator with this example →
Or price your own product: enter price, cost, category, dimensions and ad spend; the tool applies the official 2026 US rate card automatically, solves the break-even price, and models storage, returns and inbound placement. Everything runs in your browser — zero data is stored or uploaded.
Pair it with the free Amazon Product Sourcing Scorecard to score demand, competition and compliance risk before ordering inventory.
Net margin = (selling price − referral fee − FBA fulfillment fee − fuel surcharge − advertising − inbound freight − storage − return amortization − item cost) ÷ selling price × 100. Amazon's 2026 US fees apply the official non-peak schedule from Jan 15 to Oct 14, plus a 3.5% fuel & logistics surcharge from Apr 17.
A typical 2026 example: $30 price, 15% referral fee ($4.50), large-standard fulfillment $4.20, 3.5% fuel surcharge $0.15, advertising $3.00, inbound freight $1.50, 8% return amortization ~$1.35, storage ~$0.04 and placement ~$0.30. That is about $15.04 of fees — roughly 50% of the selling price; subtract an $8 item cost and the unit nets $6.96 (23.2% margin).
Most successful sellers target 20–30% net margin per unit after all fees and advertising. Below 10%, a return wave or Q4 storage spike can turn the SKU negative, so the useful test is price at least 20% above break-even, not the margin alone.
Amazon's 2026 US schedule (effective Jan 15, 2026) updates fulfillment bands for small-standard and large-standard sizes, adds new weight bands for larger items, and the 3.5% fuel & logistics surcharge applies from Apr 17, 2026. Holiday peak fees run Oct 15, 2026 – Jan 14, 2027.
Break-even price is the selling price where net profit equals zero after every fee. The FBA Calcs calculator solves it by binary search across the full fee structure — including referral tier boundaries like beauty flipping at $10 — and rounds to the cent.
Yes. Apparel return rates run 20–30% and each return costs referral plus fulfillment plus processing fees. Storage costs $0.78 per cubic foot off-peak and $2.40 in Oct–Dec, so slow movers quietly lose margin. Both are modeled in the free FBA Calcs calculator's advanced costs section.