Last updated October 8, 2026
In short: The free tools run in your browser, with no account. If you sign up for Pro, we store your email, your subscription status and, so it can sync, your tracker. We don't sell your information.
GavelMath (gavelmath.com) is a set of profit calculators and a show tracker for online sellers, operated by Stopmere LLC, a Florida limited liability company. In this policy, "we" and "us" mean Stopmere LLC, doing business as GavelMath. You can reach us at hello@gavelmath.com.
The prices, costs and fee rates you enter, any CSV list you paste or upload for the bulk check, the items, shows and sales you record in the show tracker, and any Whatnot report you import (including buyer usernames and states it contains) are processed by your own browser. On the free plan they are not sent to us or stored on our servers. If you have Pro and are signed in, your tracker is also saved to your account so it syncs between devices (see below).
To save you retyping, the site stores information in your browser's local storage on your device: the fee rates you edited, the screen you last used, and your show tracker inventory, shows, sales and tracker settings. This stays on your device and we can't see it.
Because it lives only in your browser, clearing this site's data, using a private window, or switching to another device or browser means it won't be there. Use Export CSV backup in the tracker to keep your own copy.
If you're signed in, your browser also keeps a sign-in token so you stay signed in.
To use Pro you sign in with your email address. We email you a sign-in link; there's no password. We store your email address and your subscription details (plan, status and renewal date).
While you have Pro and are signed in, your show tracker (items, costs, shows, sales, refunds, giveaways, expenses, tips and settings, plus any data you imported from Whatnot reports, which can include buyer usernames and states) is stored in our database so you can use it on more than one device. Only you can read it; other users can't.
If your Pro subscription ends, your synced tracker stays in your account for 12 months in case you come back, and it stays on your device. You can ask us to delete your account and all synced data at any time by emailing hello@gavelmath.com.
If you email us, we use your message and address only to reply and help you. If you buy Pro, we may email you about your subscription. We don't send marketing email unless you ask for it, and every marketing email will include a way to unsubscribe.
We don't sell your personal information, and we don't share it for advertising. We share it only with the service providers above to run the site, or when the law requires it.
GavelMath is meant for adults running a selling business. We don't knowingly collect information from children under 13.
You can use the free calculators and tracker without giving us any personal information. You can cancel Pro at any time from Account → Manage or cancel subscription. If you've contacted us or have an account, you can ask us to show you, correct or delete the information we hold about you by emailing hello@gavelmath.com.
If we change this policy, we'll update the date at the top of this page. If a change is significant, we'll also note it on the site, and email Pro subscribers.