Pricing backwards: the price your costs actually demand
Most sellers price forwards — pick a price, then discover the profit. Repricers make it worse, copying competitor floors that were computed with flat-percentage guesses until the floor sits below break-even. This calculator runs the other direction: give it your full cost stack and the margin, ROI or per-unit profit you refuse to go below, and it walks the price upward cent by cent through Amazon's real fee structure — referral bands, tiered categories, fulfillment price bands, the fuel surcharge, ads and expected returns — until the target is met. The first price that clears your target is your floor; anything below it is a donation.
A closed-form shortcut cannot do this honestly: the referral rate itself changes with price (a clothing item pays 5% at $15, 10% at $20 and 17% at $20.01, on the whole price), and the fulfillment fee steps between price bands. Solving numerically through the same fee engine as the Amazon FBA Calculator keeps every jump in the answer.
Worked example
At the defaults — the same $8 gadget as the FBA calculator with peak-season toggles on, a 20% margin target — the solver lands at $28.43: $1.56 below the $29.99 the forward example used, because the target, not the market, set the number. For clothing it also warns when your answer parks just under a referral cliff, where raising the price a dollar would drop the rate band against you.
How to use this calculator
- Choose what you are solving for: margin if you think in percentages of price, ROI if you think in return on the cash tied up per unit, profit if you need a fixed dollar per sale.
- Enter every cost honestly — the solver can only protect you from costs it can see.
- Take the minimum price as your floor: your repricer minimum, your coupon floor and your lightning-deal floor all derive from it.
- Check the break-even price too — the gap between break-even and your target price is your room to discount.
Why the answer is a range in real life
The fee schedule is the 2026 schedule (estimates, as on the FBA calculator): referral bands are Amazon's published table, fulfillment uses the three price bands with the 3.5% fuel surcharge and the holiday peak toggle. Your settlement can still differ where Amazon measures a different size tier than you entered. Re-solve whenever a cost changes — freight and ad rates move more often than prices should.