Calculator inputs: never collected
Every calculator on this site is static and runs entirely in your browser. When you move a slider or type a number, the result is computed locally using standard JavaScript math, and that number never leaves your device. There is no server endpoint that receives calculator inputs, no database that stores them, and no log file that records them. This is true for every page on the site, without exception.
Analytics
This site uses Google Analytics (GA4) to understand aggregate traffic: which pages are visited, roughly how many visitors arrive, which country or referring site they came from, and what device type they used. Google Analytics operates independently of the calculators; it never receives the values you type into any input field, slider or form on this site, only the fact that a page was viewed. If you prefer not to be measured, a browser extension that blocks Google Analytics, or Google's own Analytics opt-out browser add-on, will stop this collection without affecting any calculator's functionality.
What Google Analytics receives
Google Analytics typically records an approximate location derived from IP address (city or region level, not a precise address), browser and device type, the page visited and how it was reached, and how long the visit lasted. Google's own privacy policy governs how that data is processed and retained; this site does not have access to individually identifying records and does not combine analytics data with any other source to build a personal profile.
Cookies
Google Analytics sets first-party cookies to distinguish visits and avoid over-counting a single visitor as many separate ones. Separately, the site may set a strictly necessary cookie or local storage entry to remember your selected language so it does not reset on every visit. No advertising cookies are set, and no cookie on this site is used for cross-site tracking or ad targeting.
Fonts and other resources
Inter and Space Grotesk, the two typefaces used across the site, are self-hosted: the font files are served directly from this domain, not from Google Fonts or any other third party, so no font request ever reaches an external server or exposes your IP address to a font provider.
No sale of personal data
We do not sell, rent or otherwise share personal data with third parties for their own marketing purposes. Aggregate, non-identifying analytics data is processed by Google Analytics as described above; nothing else leaves this site.
Your choices
You can clear cookies at any time through your browser settings, use a content blocker to prevent analytics scripts from loading, or browse in a private window to avoid persistent identifiers. None of these choices affect any calculator's accuracy or availability, since every calculation happens locally regardless of analytics or cookie settings.
Children's privacy
This site is a general-audience reference and calculation tool. It is not directed at children and does not knowingly collect personal information from children. A parent or guardian with a concern about a child's use of the site can reach out through the contact form below.
Legal basis and international visitors
Visitors reach this site from many countries, and data protection rules differ between them. Regardless of jurisdiction, the practical position is the same everywhere: calculator inputs never leave your device, and the only data collected is the aggregate, non-identifying analytics traffic described above, processed under Google's own data processing terms for Analytics. Where a specific regional law grants additional rights, for example a right to request what data is held about you, the honest answer for this site is that no individually identifying calculator or usage data exists to hand over, since none is collected in the first place.
Data retention
Aggregate analytics data is retained according to Google Analytics' own default retention settings rather than a custom schedule set by this site. Because analytics here is used only in aggregate, to see which pages are useful, there is no individual visitor record retained by this site outside of what Google Analytics itself stores under its own policy.
Security
The site is served entirely over HTTPS, and because there is no login system, no database of user accounts and no server-side storage of calculator inputs, there is no user data at rest to secure beyond the aggregate analytics already described. The smaller the amount of personal data a site holds, the smaller its exposure if anything ever goes wrong, and this site is built to hold as little as the calculators genuinely require, which in practice is none.
Contact form
The contact form sends messages through Formspree; their privacy policy applies to messages you submit through that form. Do not include sensitive personal information, such as financial account numbers or medical details, in a contact message.
Do Not Track and browser signals
Some browsers send a Do Not Track or Global Privacy Control signal with every request. This site does not currently distinguish between visitors who send that signal and those who do not, since Google Analytics is the only tracking-adjacent technology in use and it can be blocked directly through the browser or extension methods described above regardless of any signal support.
Changes to this policy
This page may be updated as the site's tools or analytics setup change. Material changes will be reflected here directly; there is no separate mailing list or notification system since the site does not collect the contact information needed to run one.