A plain-language policy for a small, non-commercial educational site. Last updated October 26, 2026.
The short version
This site collects no personal information. It has no sign-up form, no accounts, no comments and no contact form.
What happens to what you type
The numbers you enter into the calculators stay in your browser. They are not sent to us or to anyone else, and they are not stored.
Cookies and tracking
The site currently uses no advertising cookies and no analytics. If that changes, this page will say so before it does.
Hosting
The site is hosted on Cloudflare, which processes standard web-request data (such as IP address and browser type) to deliver and protect the site. We do not use that data to identify visitors.
If you email us
If you write to , we will see your email address and message. We use them only to reply (for example, to fix an error you reported) and do not sell or share them. Ask us to delete your message at any time.
Changes
If we change this policy — for example by adding a sign-up form — we will update this page and the date above before it takes effect.