Privacy Policy

What happens to the numbers you enter

The compound interest calculator and the savings goal calculator both do their math entirely inside your browser, using JavaScript. Your principal, contribution amount, savings goal, interest rate, time period, and any other value you type is never sent to a server, never logged, and never stored in any database on this site. There is no form anywhere on this site that transmits your calculator inputs anywhere.

This is a direct consequence of how the site is built: it is a static site with no backend that receives, processes, or stores what you type. There is no infrastructure on this site's side capable of receiving those numbers, even if someone wanted to.

Theme preference and saved calculator values

The only things this site saves on your device are your light/dark theme preference and your last entered values for each calculator, stored in your browser's localStorage. This does not identify you, is never sent to any server, and only exists so the page can remember your preferences and inputs on your next visit. You can clear it at any time by clearing this site's data in your browser.

The feedback button

Below each calculator there is an optional thumbs-up / thumbs-down feedback button. Clicking it sends an anonymous signal (just the vote count, no information that identifies you, no stored IP address, no tracking cookie) to this site's backend, purely so the count can be tallied. A local marker in your browser prevents you from being asked to vote again repeatedly, but that marker does not identify you personally, it only stops a second vote from the same browser.

Analytics

This site may run Cloudflare Web Analytics, a privacy-focused analytics service that does not use cookies or collect personally identifiable information, and does not track visitors across other websites. It reports aggregate metrics only, such as how many pages were viewed and roughly how long a page took to load.

The only other technical information involved is the standard request-level data (source IP address, browser type, request time) that Cloudflare's network processes automatically to deliver the page to your browser, the same way any hosting provider does. That falls under Cloudflare's own privacy policy as the network operator, and is not accessed, exported, or combined by this site to identify visitors individually.

Cookies

This site does not use advertising tracking cookies or third-party profiling cookies. The only local storage used is the localStorage mentioned above, for theme preference and calculator values, which is technically not a cookie and is not automatically sent to any server with every request, unlike a traditional cookie.

Hosting and infrastructure

This site is hosted on Cloudflare's network, which processes the technical requests needed to deliver the page to your browser (source IP address, browser type, request time), the same way any hosting provider does. That technical infrastructure data falls under Cloudflare's own privacy policy as the network operator, and is not accessed, exported, or combined by this site to identify visitors individually. No hosting information is used for any purpose beyond delivering the pages and assets (CSS, JavaScript, images) that make up the calculators.

What this site does not do

To be explicit rather than vague: there is no user account system, no login, no email newsletter signup, no advertising network, no remarketing pixel, and no sale or sharing of visitor data with data brokers. The three calculators, the formula reference page, and this privacy page are the entire functionality of this site, and none of them require, request, or benefit from collecting personal information, so none is collected beyond the anonymous, aggregate analytics described above.

This site is not financial advice

The calculators and reference content on this site are provided for general educational and planning purposes only. They illustrate how compound interest math works given the numbers you enter: they do not predict future interest rates, investment returns, or market performance, and nothing on this site should be treated as personalized financial, investment, tax, or legal advice. Consult a qualified professional for advice specific to your own situation.

Changes to this policy

If the way this site collects or handles data changes in the future (for example, if a new feature required saving something on a server), this page will be updated to reflect that change before it takes effect. There is no fixed review schedule, but the commitment is to keep this text matching what the tools actually do, not a generic description copied from elsewhere.

Why a static, browser-only calculator is more private by design

Many online financial calculators send your inputs to a server to perform the calculation, which means your principal, savings goal, or interest rate assumptions pass through a third party's infrastructure even briefly. This site was built the opposite way on purpose: the JavaScript that computes your future value or required monthly contribution ships to your browser once, as part of the page, and every subsequent calculation happens on your own device using your own processor. Nothing about your specific numbers ever needs to leave your computer or phone for the tools to work, which is a structural privacy guarantee rather than a policy promise that depends on trusting a server operator to behave.