Effective October 8, 2026.
Nothing. All calculations run on your computer. Your inputs, the date your free trial started and your Pro status are saved in your browser's extension storage so the calculator remembers them. Uninstalling the extension deletes them.
The only network request is to ExtensionPay (extensionpay.com) to check whether you have purchased Pro. It identifies the extension install, not your calculations.
The optional Pro upgrade is processed by ExtensionPay and Stripe. They receive your email address and payment details under their own privacy policies. The developer never sees your card number.
No data is sold, shared with third parties, or used for advertising, credit or lending decisions.