In short: Kalkulo does not collect personal information, uses no tracking cookies, and requires no login. Details below.
We use GoatCounter to see which calculators are actually used — without it, further prioritization is pure guesswork. GoatCounter is chosen because it's cookieless and doesn't permanently store your IP address or other personal information: the IP is only used briefly (in memory, not in a database) to estimate which country the visit comes from, and is then discarded. What's stored is aggregated, anonymous numbers — page views, browser/OS type, screen width and referring page — nothing that can be traced back to you as an individual. The data is hosted in the EU (Germany/Finland).
The site is static and has no backend of its own. The fonts are self-hosted — they live in our own assets folder and aren't loaded from Google or other third parties. Three exceptions exist, all on specific Norwegian-language calculators:
The site sends a Content-Security-Policy header that restricts which domains the site itself can load scripts, styles and data from (only ourselves, plus the services mentioned above), along with a couple of other standard security headers. This is an extra layer of defense on top of what's described above — it doesn't change what's collected.
Calculators embedded on other websites via our embed code work the same way — no data is sent to Kalkulo.
Questions about privacy can be sent to kalkulo.app@gmail.com.