About OpenFeeCalculator

OpenFeeCalculator is an independent fee and profit calculator for US marketplace sellers. It is operated by Alex Builds Studio, written by Alex, and is not affiliated with, endorsed by, or sponsored by eBay, Etsy, Poshmark, Mercari, PayPal, Depop, Whatnot, or any other company named on this site. The homepage is an eBay fee calculator because that is the search intent we chose to serve first; other official US schedules sit on their own pages, and a comparison of every platform we cover is free.

Why the tool exists

Sellers lose money when they apply the right-sounding percentage to the wrong base. eBay's official US final value fee is not 13.6% of the item price alone. Poshmark's 20% is not the same shape as Mercari's 10%. Casual blog posts flatten those differences and go out of date. This site keeps rates in dated JSON that links to official pages, runs the math in your browser, and publishes the methodology and a changelog so a number can be checked. We do not invent user counts, star ratings, or testimonials.

Who operates it

Alex Builds Studio operates OpenFeeCalculator. Author credit is Alex / Alex Builds Studio. The contact address is alexbuildsstudio@gmail.com. Every calculator, the full comparison grid, reverse pricing and batch tools are free. The site is not a marketplace, a payments company, or an official partner of the platforms it calculates.

Trademarks

eBay, Etsy, Poshmark, Mercari, PayPal, Depop, Whatnot and other product names are trademarks of their owners. They appear here only to identify the fee schedules being calculated. Use of a name does not imply any partnership, certification, or official status. If a rights holder needs a correction to how a name is presented, email the address on the contact page.

How to use this calculator

1. Read the methodology. Sources, tax treatment and rounding are written down, not implied.
2. Use the calculators as estimates. Your official statement is the record that matters.
3. Write if a rate looks wrong. Send the official URL to alexbuildsstudio@gmail.com.
4. Use any calculator without creating an account. Comparison, reverse pricing, batch and share tools are included at no charge.

Frequently asked questions