Marketplace Price and Margin Calculator

Selling on a marketplace, the listing price is not the money you keep. Commission, a fixed fee per order, payment charges, fulfilment by weight, storage, advertising and returns each take a share, and a product that looks fine at the listed price can lose money once returns are counted. Many sellers only find out from the monthly statement.

Enter the fees of a sales channel exactly as your own rate card shows them: commission % (on the price with or without VAT), fixed fee per order, payment fee, fulfilment bands by weight or a flat fee, storage per unit per month, ad cost per unit or as a percent of the sale, return rate, the cost of handling a return, how much of returned stock you can resell and how much commission comes back on a refund. Add products (SKU, cost, price, weight). The app shows expected net profit per unit and margin, the minimum viable price for the margin you want, and a what-if grid of price changes against return rates. A batch table scores the whole list and flags products that lose money. Import the product list from CSV and export the results.

What is inside:

• Channel fees, Products, Profit per unit, All products, What-if and How it works tabs
• Several channel profiles, so one product list can be tested on each channel
• Prices with or without VAT, handled as a setting
• Print / Save as PDF, CSV in and out, JSON backup
• An invented example (clearly marked) and EXAMPLE-DATA files

Fees and commission rates are settings only. The app contains no marketplace fee schedule and no platform names or logos: check your current rate card and type the numbers in. It is not tax or legal advice, not an FTA-approved system, and no platform or courier endorses it.

How it differs from the pricing and margin workbooks in the catalogue: those are spreadsheets for one product at a time. This app handles the expected cost of returns, solves for the minimum viable price, runs a what-if grid and scores a whole CSV of products in one go.

Tested: every calculation was compared with an independent Python (Decimal) calculation on randomised cases, CSV edge cases (quotes, commas, Arabic text, byte order mark) were run through the importer, and the screens were driven in a headless Chromium browser at phone and desktop widths. It has not been tested on a real phone, in Safari, Firefox or Edge.