Privacy
It describes the site as it works today. CardMath does not run accounts, does not collect card-application data, and does not ask for a credit profile.
What stays in this tab
The tab always stores the session id, the last card page, the last guide, and the scroll position. If the address includes utm_source, utm_medium, utm_campaign, or utm_content, it stores those too, and only those. The tab drops all of it when you close it. These are not cookies. CardMath's own pages don't set a cookie, and it does not use local storage.
What the site records
It sends a first-party event to CardMath. That event is the kind of view, the path, a card slug when there is one, and the session id. On the calculators it can also include the prior card or guide. If an address you open in a tab includes utm_source, utm_medium, utm_campaign, or utm_content, that tab's events include those values from then on, until another address with them replaces them. When you open a card issuer's site from CardMath, it sends a separate event with the card, the issuer, and any of those four fields, but not the session id. None of these events include the amounts you type, your income, or anything that identifies you.
Calculators
The homepage, the worksheet, and compare take numbers and a card choice. Those stay in the page. There is no contact form. Email support@cardmath.net if you have a question.
Links
A link appears only when that card has one, and it goes to the issuer's own page. Issuer sites have their own privacy policies.