Cookie Policy
Which cookies the site uses, why, and how you can manage them.
What is a cookie?
A cookie is a small text file a site stores in your browser so it can recognise you on the next page or visit. The browser’s local storage can be used for the same purpose.
Essential cookies and storage
These are needed for the site to work and are not used for advertising or tracking. Without an account, the session cookies are never created.
- cf_user (cookie, 30 days): keeps you signed in. Readable by the server only (HttpOnly).
- cf_u (cookie, 30 days): a marker with no personal data that tells the page you are signed in.
- cf-theme (local storage): your light or dark theme choice.
- Offline cache (service worker): copies of pages kept in your browser so they open without a connection.
Statistics and advertising cookies
The site currently uses no statistics or advertising cookies. This page will be updated if that changes.
How do I turn cookies off?
You can delete or block cookies in your browser settings. If you block the essential cookies you cannot sign in or save calculations; the calculators still work.
The theme choice and offline cache can be removed with your browser’s “clear site data” option.