Nothing. The calculator is a single web page that runs entirely on your device. It has no login, no database, and no back-end that receives your financial information.
Any figures you enter are processed in your browser to compute the estimates, and are auto-saved in your browser's localStorage on that one device so the page remembers them next time. If you click "Download file," a file is saved to your own computer. In both cases the data never leaves your machine — we cannot see it, and there is no way for us to.
To erase locally saved data, use the "Clear form" button, or clear this site's storage in your browser settings.
This site uses Cloudflare Web Analytics, a privacy-first, cookieless measurement tool, to count visits and see which referring sites are popular. It sets no cookies, does not track you across other websites, and does not fingerprint your device or collect any personal data — it records only aggregate, anonymous page-view counts. There are no advertising scripts and no other third-party trackers. (Offline copies saved with "Download this tool" have the analytics script removed entirely and make no network calls at all.)
Your financial inputs are never measured or transmitted. The analytics beacon only knows that a page was viewed — never anything you type. Everything you enter stays in your browser, as described above.
The optional "current home value" field includes links to Zillow and Redfin. Those are plain links that open in a new tab — this tool never sends your address (or anything else) to them or anyone. What you do on those sites is governed by their own privacy policies.
The page is served as a static file by Cloudflare Workers. As with any website, Cloudflare may log standard, server-side request metadata (such as IP address and timestamp) for security and reliability, governed by Cloudflare's own privacy policy. This application stores no user data server-side.
This is a planning estimate for educational purposes, not financial, lending, or tax advice. Your actual loan terms, payment, and payoff figures come from your lender or loan servicer — confirm with them before making decisions.
If this policy changes, the "Last updated" date above will reflect it. Since no personal data is collected, changes are unlikely to affect you.