Essential preference storage
The local-storage key om-consent records whether you chose “essential” or “all” analytics preferences. It remains until you change your preference or clear browser data. This preference is necessary to respect your choice and does not contain your email or financial inputs.
Authentication and security
The public website does not require sign-in. An owner-only administration route uses the platform’s essential authentication session cookie when an authorized owner signs in. Infrastructure providers may also use security or routing mechanisms required to serve requests. These are not used by this application for advertising.
Optional analytics
The site emits local interaction events for book views, Amazon purchase-link clicks, sample starts, completed tool shares and successful email registrations. No email addresses or calculator figures are included in these event payloads. An optional dataLayer integration receives events only when analytics is allowed. No external analytics or advertising provider is installed by this build.
If an analytics provider is added, the operator must list its cookies, lifetimes, purposes and recipients here and ensure it is loaded only after the required consent. Accepting analytics now does not authorise undisclosed future purposes.
Other requests and sharing
Google Fonts supplies the website typefaces and may receive standard technical request information. A chosen calculator share link contains your entered figures in its query string. This is not a cookie, but those figures can remain in browser history, appear in logs when the link is loaded and be read by recipients.
Change your choice
Use “Cookie preferences” in the footer to choose again. You can also delete local storage and cookies in your browser settings. Essential-only visitors retain full access to the public features. Version date: 28 September 2026.