About Reselling Math
Who builds Reselling Math, how each marketplace fee is sourced and verified, and how to report an error in a calculator.
Updated
Who runs it
Reselling Math is built by Paul Gunder at Rocky Mountain Apps, a small company that makes calculators and reference tools. Paul writes the calculators and checks each fee against the marketplace that charges it.
Why it exists
Most sellers know their marketplace's headline percentage. Fewer know what it's a percentage of. eBay charges its final value fee on the shipping the buyer paid and on the sales tax, and Whatnot and Depop charge payment processing on the tax too. Mercari takes its cut of buyer-paid shipping. Working out a fee on the item price alone makes a sale look more profitable than it is. These calculators use the full base each marketplace actually charges on, so the payout matches what lands in your account.
How it's paid for
The site is free to use. Ads may appear on it later. The LensLumi links on the calculator pages go to our own app, which turns phone photos into listing photos and drafts listing text. No marketplace pays us, and none of them has any say in what the calculators show.
Your numbers
The calculators run in your browser. While you use one, nothing you type is stored or sent anywhere: the numbers go into the page's address instead, so you can bookmark or share a result. That also means anyone you send the address to sees the same numbers. Like any web address, it reaches the site's web host when the page is opened or reloaded.
Get in touch
Found a wrong fee, or want a marketplace added? See the contact page.