Add marketplace fees and other percentage costs

Some costs are a share of the selling price, not a fixed amount: marketplace commission, card fees, delivery app commission. Add them under Costs that are a % of the sales price.

Choose a platform under Where do you sell? to add that platform's usual fees as editable rows. Rates change, so confirm them with the platform and edit the numbers if yours differ.

Percentage costs are taken from the selling price, which is why a simple mark-up on cost often leaves less profit than planned. The calculator solves for the price that still delivers your margin after these fees.