How this calculator works
For a profit target, the engine solves seller revenue − marketplace fees − seller costs = desired profit. For a margin target, it solves net profit ÷ seller revenue = desired margin.
- Enter item cost, fulfillment and operating costs, the percentage rate, fixed fee, and the exact fee basis.
- For target profit, test candidate prices until net profit is at least the desired dollar amount.
- For target margin, test candidate prices until net profit divided by seller revenue reaches the desired percentage.
- The engine uses a bounded binary search, rounds the required result to cents, then feeds that price through the normal forward calculator as verification.
Worked example
Example: price for $25 profit after a 10% fee
Assume a $20 item cost, $5 actual shipping expense, no buyer shipping, a 10% fee on item price, a $0.30 fixed fee, and a $25 target net profit.
- Required price before cent rounding solves: price − 10% of price − $0.30 − $25.00 costs = $25.00 profit.
- That is 0.90 × price = $50.30, or approximately $55.89.
- At $55.89, the percentage fee rounds to $5.59; with the fixed fee, total fees are $5.89.
- Seller revenue of $55.89 minus $25.00 operating costs and $5.89 fees verifies $25.00 profit.
The verified required price is $55.89. A different fee basis, buyer shipping amount, minimum fee, category tier, or tax treatment can change the result and should be modeled with the marketplace-specific tool.
Important exceptions
- This custom reverse model supports one percentage and one fixed fee; marketplace-specific tiers, caps, minimums, and conditional charges are not inferred.
- A target margin must be below 100%, and an extremely high target may have no solution within the calculator's supported price range.
- Cent rounding can make the verified profit a cent above the requested target.
- Sales velocity, returns, inventory carrying cost, income tax, and opportunity cost are not predicted.
Assumptions used
- The fee inputs and selected basis have been checked against an official source or seller statement.
- The required price is for one unit and one fixed order fee.
- All entered costs are attributable to that unit or intentionally allocated per unit.
- The forward verification uses the same calculation engine and rounding rules as the displayed result.
Sources and verification
Marketplace defaults come from the sources below. We do not use blog summaries as fee authority. User-specific or unverifiable charges stay editable.
Frequently asked questions
What is the difference between target profit and target margin?
Target profit is a dollar amount left after fees and costs. Target margin is that profit divided by seller revenue, expressed as a percentage.
How does the calculator verify the required price?
It feeds the solved cent-level price back through the same normal fee and profit calculation and displays the resulting payout, profit, and margin.
Why can the verified profit be one cent above my target?
The required selling price and individual fee lines are rounded to cents. The calculator chooses a price that reaches or slightly exceeds the target after that rounding.
Should sales tax be included in my target selling price?
Sales tax collected from the buyer is not seller revenue. Include it only in the fee basis when the official marketplace policy charges fees on buyer tax.
Fee-change history
Forward-verified reverse solver introduced
Target-profit and target-margin prices are solved to cents and checked through the standard calculation engine.
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