Privacy

Calculations are local

Every calculator on this site runs entirely in JavaScript in your browser. When you type a test statistic or paste a column of data, that input is processed on your own device and never transmitted anywhere. There is no calculation API, no server-side processing, and no database.

This is a structural property, not a policy promise. The site is served as static files. It has no backend that could receive your data. You can verify this yourself: open your browser's network tab, run a calculation, and observe that no request is made.

The practical consequence is that this site is safe to use with data you could not paste into an arbitrary web tool — patient measurements, salary figures, unreleased commercial results. It also means the calculators keep working with no network connection at all.

A note on shareable links

The calculator writes your inputs into the page URL so you can bookmark or share a result. This happens locally in your browser's address bar and is not sent to us.

Be aware, though, that if you share that link, the values are visible in it — and if you paste it into a chat app or email, it travels with them. For sensitive data, use the calculator without sharing the URL. Note also that browsers record visited URLs in local history.

Local storage

The site stores exactly one thing in your browser: your light or dark theme preference, under the key theme. It never leaves your device and is not used for identification. Clearing your site data removes it.

Google Analytics sets its own cookies — _ga and a property-specific _ga_* — which hold a randomly generated identifier used to tell a returning visit from a new one. They are not linked to a login or an account, because there is neither. See the analytics section below.

Third-party requests

Fonts are requested from Google Fonts, which means your browser makes a request to fonts.googleapis.com and fonts.gstatic.com when you load a page. Google receives your IP address and user agent as part of any such request. No calculator data is included.

If your browser's language is not English, the page is machine-translated by Google Translate, which loads a script from translate.google.com. English visitors never make that request.

There are no advertising networks and no embedded trackers.

Analytics

This site uses Google Analytics 4 to count page views and see which calculators people actually use. That loads a script from googletagmanager.com and sends Google the standard set of measurement data: the page you viewed, referrer, approximate location derived from your IP address, device and browser, and the cookie identifier described above.

Nothing you type into a calculator is included. No test statistic, no pasted data, no result, and no query string from a shareable link is sent to Google or anywhere else. Only the page path is recorded. That boundary is architectural — the calculators have no network code at all — and it is unaffected by analytics being present.

You can opt out with any content blocker, with your browser's Do Not Track or anti-tracking settings, or with Google's official opt-out add-on. The calculators work identically either way.

Server logs

Like any website, the host serving these files may keep standard access logs — the page requested, timestamp, IP address, and user agent. These are a property of how the web works and contain no calculator inputs. They are not used to build profiles.

Changes

If this policy changes materially — in particular, if advertising were ever introduced — this page will be updated and the date below revised. Analytics was added on 10 August 2026, and this page was revised then. The commitment that calculations stay in your browser is architectural, and is not intended to change.

Questions

Questions about this policy go to the contact page. This policy forms part of the site's terms and conditions.

Last updated: 10 August 2026