Almost nothing. Every calculation on this site happens client-side, in JavaScript on your device. We have no accounts, no databases of your inputs, no tracking of what you earn or owe. The site is fully usable with JavaScript-blocked analytics.
We show ads through Google AdSense to keep the tools free. Google and its partners may use cookies — including the DoubleClick cookie — to serve ads based on your visits to this and other sites. You can opt out of personalised advertising at adssettings.google.com, and learn more at aboutads.info. Third-party vendors use cookies to serve ads based on prior visits; you can opt out of some third-party vendors' use of cookies at aboutads.info/choices.
We may measure aggregate page views to improve the tools. This is anonymised and never tied to anything you type into a calculator.
Questions or removal requests: reach us via the channel where you found us. We respond.