The calculators run in your browser. We do not ask for, and do not store, your name, email or any personal details, and nothing you type into a calculator is sent to us.
The site remembers your light or dark display choice in your browser's local storage. Our web host keeps standard server logs (such as the page requested and your IP address) for security and reliability.
Links to Amazon are affiliate links. If you click one, Amazon may set cookies and will tell us that a purchase qualified, without telling us who you are. See Amazon's own privacy notice for what it collects. If we add advertising or analytics in future we will update this page first.
Last updated 7 November 2026.