Profit Margin Calc is an independent educational website. We build free, fast calculators and plain-language reference pages about small-business and seller math: profit margin, markup, gross and net margin, contribution margin, break-even, pricing, freelance rates, and the fees eBay, Etsy, Amazon, resale apps, Shopify, PayPal, Stripe, Square and card processors charge per sale.
What we do
- Calculators you can check. Every calculator shows its formula and a worked example, so you can verify any result by hand.
- Fee schedules with dates. Seller and payment fees come from each platform's own fee pages and help articles. Each fee page names its source, the date we last checked it and a log of past fee changes.
- Reference data with sources. Definitions and benchmarks come from primary sources: the IRS, the U.S. Census Bureau, the SBA, the Federal Reserve, card-network rate publications, university datasets and open textbooks.
- No selling. We do not sell products, we do not link to sellers, and we do not accept payment for reviews or placements.
Who we are
Profit Margin Calc is run by a small independent editorial team based in Türkiye. We are not affiliated with any marketplace, payment company, card network, accounting firm or government agency mentioned on this site.
How the site is funded
The site shows advertising served by Google AdSense. Advertisers do not influence what we write, and ads are clearly separated from our content.
Read our editorial policy, our disclaimer and our privacy policy. To reach us, use the contact page.