Privacy

The calculator runs in your browser

All arithmetic happens in JavaScript on your device. When you share a result, the inputs are written into the part of the link after the “#” (the fragment). Browsers do not send the fragment to any server, so a shared scenario cannot appear in our logs or anyone else’s.

Anonymous usage events

The page sends a small first-party message to this site’s own server when a page is viewed and when the calculator is used. Each record holds: the time, the page path (no query string), the event name (for example “pageview”, “calc_interact”, “state_select”, “calc_complete”, “share”, “source_click”), a short label such as the two-letter state chosen, a random identifier created for that single page view and discarded when you leave, the host name of the referring site, your country as reported by our network provider, and whether the device is mobile or desktop. Automated clients are filtered out.

We do not store IP addresses, user-agent strings, cookies, persistent identifiers or any number you type into the calculator. There are no third-party scripts, ad networks, pixels or analytics vendors on the site, so nothing about your visit is shared with them.

Corrections you send

If you use the corrections form we store the page it concerns, the kind of issue, your message, an optional reply address if you give one, and the date. We use the reply address only to follow up on that report. We do not store your IP address or browser details with it.

Local settings

If you switch between dark and light themes, the choice is saved in your browser’s local storage on your device only. Clearing site data removes it.

Retention and requests

Anonymous events are kept as aggregate statistics. Correction reports are kept while they are useful for keeping the site accurate. To ask about or delete a report you sent, use the contact form and include enough detail for us to find it.

Hosting

The site is served by Cloudflare, which processes requests to deliver pages and protect the site; our own storage is limited to the records described above.