Privacy policy

Last updated: 2026-10-07

What we collect

The calculators run entirely in your browser. The numbers you type are not sent to or stored on our servers. If you copy a result link, your inputs are placed in that link’s address so it can reproduce the result. If you switch between US and metric units or pick a currency for prices, that choice is saved in your browser’s local storage so the next page opens the same way. Prices you change in a planner’s “Your local prices” section are saved there too, so the other planners can use them; Reset clears them. None of this leaves your device.

Contact form

If you send a message through the contact form, we receive the topic, the page you mention, your message and, if you give it, your email address. The message is stored in our private issue tracker on GitHub and emailed to us; your email address is only emailed to us, so we can reply. Messages are read by us and by the automated tools that help maintain this site, and are used only to answer you and improve the site. To block spam, the form uses Cloudflare Turnstile, which checks your browser for signs of automated use.

We use Cloudflare Web Analytics, a privacy-first analytics service that does not use cookies or track you across sites, to count page views. Our hosting provider (Cloudflare) processes standard server logs, such as IP address and browser type, for security and reliability.

Advertising and cookies

We use Google AdSense to show ads. Third-party vendors, including Google, use cookies to serve ads based on your prior visits to this and other websites. Google’s use of advertising cookies enables it and its partners to serve ads based on your visits to this site and/or other sites on the Internet. You can opt out of personalized advertising by visiting Google Ads Settings or aboutads.info. See how Google uses information from sites that use its services.

Visitors in the EEA, the UK and Switzerland are shown a consent message, provided by our advertising partner, before personalized ads are used.

Affiliate links

Some pages contain affiliate links. If you buy through them, the retailer may set a cookie to attribute the sale. We do not receive any of your personal information from these retailers.

Your rights

Because we do not store personal data from the calculators, there is usually nothing for us to access, correct or delete. For requests about analytics or advertising data, use the contact form or contact the relevant provider. We delete contact form messages on request.

Children

This site is not directed at children under 13, and we do not knowingly collect their data.

Changes

We will update this page if our practices change.