Last updated October 8, 2026
In short: GavelMath gives estimates, not guarantees. Check important numbers against your own Whatnot statements. Pro is billed monthly or yearly and you can cancel any time.
GavelMath is operated by Stopmere LLC, a Florida limited liability company ("we" or "us"). By using gavelmath.com you agree to these terms. If you don't agree, please don't use the site. Questions go to hello@gavelmath.com.
GavelMath provides calculators that estimate marketplace fees, profit, break-even prices and purchase limits for online sellers, and a show tracker for recording inventory and sales. GavelMath is an independent tool. It is not affiliated with, endorsed by or sponsored by Whatnot or any other marketplace.
Calculator and tracker results are estimates based on the numbers you enter and on fee rates we believe were current when we last checked. Marketplaces change their fees, apply different rates to some categories and promotions, and can charge for refunds, chargebacks and taxes in ways a calculator can't predict. You can edit the fee rates the calculators use.
You are responsible for checking results against your own payout statements before making buying, pricing or business decisions. GavelMath is not financial, tax, legal or accounting advice.
Free includes the profit, break-even and max buy calculators, the bulk check summary for any list with details for the first 10 items, and the show tracker for up to 25 items, including lots, giveaways, refunds, expenses, show recap images and Whatnot report imports.
Pro includes everything in Free plus unlimited show tracking and report imports, the yearly summary, bulk check details for every item, and CSV export. We may add features to either plan over time, and we'll describe what's included on the site.
You need an account, linked to your email address, to buy and use Pro. Keep access to that email secure, since sign-in links are sent there. One subscription is for one person's business; please don't share your account.
On the free plan, show tracker data is saved only in the browser on the device you use. It is not stored by us, so we can't recover it if it's lost. Clearing your browser's site data, using a private window, or changing devices or browsers can remove it. With Pro, your tracker is also synced to your account, but syncing can fail or be delayed, so keep backups anyway.
You're responsible for keeping backups using Export CSV backup. We're not liable for tracker data that is lost, deleted or unavailable. Tracker results and the yearly summary, like all GavelMath results, are estimates. They are not tax advice and are not a substitute for your own bookkeeping, tax records or the tax forms Whatnot sends you.
If you subscribe while we offer founding member pricing, you keep the price you signed up at, monthly or yearly, for as long as your subscription stays active, even if we raise prices for new subscribers. If you cancel and subscribe again later, the price at that time applies.
We may change the price of Pro for new subscribers at any time. If we ever need to change the price of an existing subscription that isn't covered by founding member pricing, we'll email you at least 30 days before the new price applies.
Please don't try to break, overload or gain unauthorized access to the site, copy it to run a competing service, or share your Pro account with people who haven't paid for it.
The GavelMath name, design, text, videos and code belong to us. You're welcome to share links to the site and screenshots of your own results.
The site is provided "as is" and "as available." We work to keep it accurate and online, but we don't promise that it will be error-free, uninterrupted or that results will match what a marketplace actually pays you.
To the extent the law allows, GavelMath is not liable for lost profits, losses from purchases or pricing decisions, lost or deleted tracker data, or any indirect or consequential damages arising from your use of the site. Our total liability for any claim is limited to the amount you paid us for Pro in the 12 months before the claim, or $10 if you haven't paid us anything.
We may update these terms, and we'll change the date at the top of this page when we do. Continuing to use the site after a change means you accept the updated terms. These terms are governed by the laws of the State of Florida, USA.