Set a price that covers percentage and fixed fees

A percentage fee changes when your selling price changes.

Adding a percentage fee to your cost can understate the price you need: the fee itself is charged on the final revenue. If variable expenses are $33.30, fees are 3% and the target contribution margin is 30%, required revenue is 33.30 ÷ (1 − 0.03 − 0.30), or about $49.701493.

If the buyer pays $5 for shipping, the product price is about $44.701493. Round upward to $44.71 to meet the target in whole cents. The calculator subtracts buyer-paid shipping only after solving total required revenue.

Variable expenses here include product cost, seller shipping, packaging, advertising, a returns allowance and fixed transaction fees. The percentage fee applies to product revenue plus buyer shipping. This is an explicit simplified fee model, not a marketplace invoice reconstruction.

If target margin plus percentage fees reaches 100%, no finite positive revenue can cover positive costs under this model. Reduce the target, change costs or use another model. The target refers to contribution before allocated fixed overhead.