About Seller Profit Math

Seller Profit Math is a small, independent site of free fee and profit calculators for people who sell online. It is written and maintained by the Seller Profit Math team.

Each calculator shows its formula, starts every fee at the figure on the platform's official fee page, says when we checked it, and lets you edit it. Where we couldn't confirm a fee, we say so instead of guessing.

Everything here is a rough estimate, not a guarantee, not financial advice. We are not accountants, and nothing here replaces your platform's own fee statement or a tax professional.

Seller Profit Math is not affiliated with any marketplace or payment company. See how we calculate and our sources.

Last updated October 22, 2026.