I made a profit calculator for Amazon sellers that breaks down FBA fees, ROI, and net profit per unit.

You plug in your product price, shipping, and costs. It gives a full breakdown of gross revenue, Amazon fees, taxes, and final margins. Everything updates live as you type.

It runs in the browser, no signups, no tracking. Just a tool I needed and ended up putting online.

https://www.monkeycalcs.com/amazon-profit-calculator

Happy to answer questions or improve it based on feedback.