SwiftPrivacy policy
Effective October 20, 2026. This notice describes the calculator site, its contact form, and the administration area.
Calculator inputs
Inputs and results are processed locally in the browser. Our calculation code does not submit their values to the server or save them in cookies or browser storage. During navigation, form values may remain in browser memory so switching language preserves the current calculation. Reloading the site restores the example.
Usage statistics
We count page requests and successful calculation events. Aggregate dimensions include page path, response status, country code, referring domain, campaign labels, and traffic classification. Full referring URLs, calculator values, and calculation results are not included. The English and Chinese page paths can be counted separately.
Crawler classification and retention
The edge collector passes request IP and browser user-agent to the backend for temporary traffic classification. Raw IP and user-agent are not stored in the analytics database. Daily aggregates are retained for up to 180 days. We do not use analytics cookies, persistent visitor identifiers, fingerprinting, or cross-site tracking. Ordinary-browser classification is not proof that a request came from a person.
Privacy preferences and hosting
Optional collectors skip events when the browser sends Do Not Track or Global Privacy Control. Cloudflare and the hosting provider still process network requests and may retain infrastructure or security logs under their policies. Visiting the site therefore involves network data even though calculations run locally.
Messages you choose to send
The contact form sends the name, reply email, subject, and message you enter to our support backend. Messages are used to investigate feedback and respond when appropriate, and are retained for up to 90 days. Avoid sensitive information. Use the same contact channel to request access or deletion, with enough detail to identify your message.
Administration, advertising, and changes
Administrator login uses an essential secure HTTP-only session cookie that expires after eight hours. Public calculator visitors do not receive that authentication cookie. This release does not load advertising tags or third-party marketing analytics. Before such services are enabled, this notice and any required consent controls will be updated.