Privacy
Last updated: 7 November 2026
In short: the calculators run entirely in your browser. What you type is never sent to us or stored by us. We use no cookies and no tracking.
Who we are
The site is run by Paolo Rossetti ("we"), the data controller for the small amount of data described below. Contact: [email protected].
What we process
- Calculator inputs: processed only in your browser. Never sent, never stored.
- Server logs: our host, Cloudflare, processes technical data such as IP address and browser type to deliver and protect the site. We may look at cookie-free visitor totals (Cloudflare Web Analytics). Lawful basis: our legitimate interest in running a secure website.
- Emails you send us: kept only as long as needed to reply. Lawful basis: legitimate interest.
- Purchases and donations: handled by Ko-fi under its own privacy policy. We receive your name, email and order details to deliver what you bought. Lawful basis: contract.
Other services the pages load
Pages load fonts from Google Fonts and the chart library from cdnjs (Cloudflare) or jsDelivr. These providers see your IP address when a page loads.
Your rights
Under UK GDPR you can ask to see, correct or delete your personal data, and object to how we use it. Email us. You can also complain to the Information Commissioner's Office (ico.org.uk).