Privacy

Short version: the calculators run in your browser, we don't use cookies, and we only store an email address if you give us one.

This site is run by Gonçalo Raposeiro, based in Lisbon, Portugal, who is the data controller. Last updated 2026-10-13.

What you type into the calculators

All calculations happen in your browser. The numbers you enter are never sent to our server. When you copy a share link, your inputs are stored in the part of the link after the # sign, which browsers don't send to servers.

Analytics

We use Cloudflare Web Analytics to count page views. It doesn't set cookies or store anything on your device, and we see only aggregate numbers such as page views, referring sites and countries. Cloudflare processes this on our behalf.

Early access list

If you join the early access list, we store your email address, your answer to the optional question if you give one, the column names of a RevenueCat export if you choose to send them (never the numbers in it), the page you signed up from and the time you signed up. We use it to tell you when the paid product is ready and to send occasional product updates. The legal basis is your consent, which you can withdraw at any time by replying to any email or writing to bgraposeiro@gmail.com. We keep your address until you unsubscribe or the product is discontinued. It's stored with Cloudflare, our hosting provider.

Your rights

Under the GDPR you can ask to see, correct, export or delete your data, and object to how we use it. Write to bgraposeiro@gmail.com. You can also complain to the Portuguese data protection authority, the Comissão Nacional de Proteção de Dados (cnpd.pt).

Changes

Other websites can embed our calculators. An embedded calculator works the same way as on this site: the math runs in your browser, nothing you type is sent to us, and the site around it can't read what you type. Page views of embedded calculators are counted with the same cookieless analytics. The optional resize script a site can add next to an embed only sets the frame's height: the calculator sends it one number, its height, and the script reads nothing from that site and sends nothing back. Loading it is an ordinary file request, like loading an image.

If we start collecting anything new, we'll update this page before we do.