Privacy
The calculator runs entirely in your browser. The numbers you type are never sent anywhere.
Last updated 2026-10-26
What happens to the numbers you enter
They stay on your device. There is no account, no server-side calculation and no database. Every figure is worked out by code running in your browser.
The one place your inputs appear outside the page is the address bar: changing a value rewrites the query string so a scenario can be bookmarked or shared. That happens locally. A link only goes anywhere if you send it somewhere yourself, and anyone you send it to will see the figures it contains.
Cookies and local storage
None. This site sets no cookies, uses no local storage, and runs no analytics or tracking scripts.
Advertising
This site currently carries no advertising. Space is reserved in the layout for it, but no ad network is loaded and no ad scripts run. If that changes, this page will be updated before any ads appear, and it will name the network and what it sets.
Server logs
The site is static files served by a host, and like any web host that involves ordinary request logs: IP address, time, the page requested, and the browser's user agent string. These are kept by the hosting provider for operational and security purposes. They are not combined with anything from the calculator, because nothing from the calculator is ever sent.
External requests
Fonts and styles are served from this site rather than a third-party CDN, so loading a page does not announce your visit to anyone else.
Your data rights
There is no account to delete and no stored personal data to request, because none is collected. Clearing your browser's history removes any saved links containing your figures. If you have a question about any of this, the contact page explains how to get in touch.