About

Fee and profit math for sellers

Seller Fee Kit helps online sellers estimate marketplace fees, payment costs, profit margins, and ad break-even points with transparent formulas.

What this site is for

The first version focuses on English-language, US-market, USD calculators. The goal is to make fee and profit estimates fast to use, easy to verify, and clear enough to support real pricing decisions.

What this site is not

Seller Fee Kit does not provide financial, tax, legal, or accounting advice. Platform rates can vary by country, category, seller plan, account status, promotion, and payment method.