Formula and worked example

Selling price = (total job cost + fixed fee) ÷ (1 − margin/100 − percentage fee/100).

For $32.86 cost, a 40% margin and no fees: 32.86 ÷ (1 − 0.40) = $54.766…, rounded up to $54.77. A 40% markup would be $46.00 and would produce only a 28.26% margin before fees.

Assumptions and limits

Margin is contribution divided by selling price, so payment fees based on the selling price belong in the denominator. Enter the complete cost first, including material, machine time, labor, expected failures, packaging and shipping. This estimate does not decide taxes, marketplace rules or what customers will pay.