The break-even price is the price where net profit hits zero — $20.57 on the standard $30 home example. Walk the full stack: referral, fulfillment, fuel, ads, freight, returns, storage, placement, cost. Everything below $20.57 is a loss, unit after unit.
| Step | Line item | Amount | Running balance |
|---|---|---|---|
| 1 | Selling price | $30.00 | $30.00 |
| 2 | Referral fee (15%) | $4.50 | $25.50 |
| 3 | Fulfillment + fuel surcharge | $4.20 + $0.15 | $21.15 |
| 4 | Advertising (10%) | $3.00 | $18.15 |
| 5 | Inbound freight | $1.50 | $16.65 |
| 6 | Returns (8%) + storage + placement | $1.35 + $0.04 + $0.30 | $14.96 |
| 7 | Landed cost | $8.00 | $6.96 net |
Per the FBA Calcs 2026 rate card: total fees of $15.04 against an $8 cost. Now reverse the question — at what price does that final row hit zero? The answer the engine solves is $20.57.
Break-even looks like one formula, but the fee stack bends as price moves: referral rates flip at category boundaries (beauty drops 15% → 8% at $10), and dimensional weight decides which fulfillment band applies. Solving "price where net = 0" across those flips is a search problem, not a sum — which is why a hand-rolled estimate lands close but not exactly.
The calculator walks the same stack for your dimensions and category and reports break-even next to net profit:
You lose money on every unit sold, by exactly the gap between price and break-even. On the worked $30 example the break-even floor is $20.57 — price at $19.99 and the SKU burns cash on each order, no matter how well the listing converts. Break-even is the floor; margin above it is what the business lives on.