Privacy Policy

What this site collects, why, and the choices you have.

Who we are

This site is published by Sumfern. You can reach us at info@sumfern.com.

Your calculator inputs

The calculators run in your browser. The numbers you type are not sent to our server by the calculator. When you use “Copy link to this result”, your inputs become part of that link’s address, so anyone who receives the link can see them.

Server logs

Our hosting provider keeps standard server logs, such as IP address, browser type and the pages requested, for security and to keep the site running.

Advertising and cookies

This site may show ads from Google AdSense. Google and its partners may use cookies or similar identifiers to show and measure ads. Visitors in the European Economic Area, the United Kingdom and Switzerland are asked for consent before personalised ads are used, and can change that choice at any time using the privacy options on the site. You can learn how Google uses information from sites that use its services at policies.google.com/technologies/partner-sites.

Analytics

We use Google Analytics 4 to count visits and see which pages are used, from which countries and on what kind of device. It may set cookies in your browser. We do not send Google your calculator inputs: the part of the page address that holds them (everything after the question mark in a result link) is removed before the address is sent, and we turn off Google signals and ad personalisation in Analytics. Visitors in the European Economic Area, the United Kingdom and Switzerland are treated as not having consented to analytics cookies, so for them Analytics stores no cookies and receives only limited, non-identifying pings. We also use Google Search Console, which reports how the site appears in Google Search and does not track individual visitors. Learn how Google handles Analytics data at support.google.com/analytics/answer/6004245.

Your rights

Depending on where you live, you may have the right to ask what data we hold about you, to correct it or to have it deleted. We do not run user accounts. To make a request, contact us at info@sumfern.com.

Children

This site is not directed at children.

Changes

We may update this policy. The date of the latest change is 13 October 2026.