Privacy policy
Last updated 2026-11-14.
What you type into calculators
All calculations happen in your web browser. The numbers, names and dates you enter are never sent to us or anyone else, and they aren't saved. Closing or refreshing the page clears them.
What the site itself collects
The site has no accounts, no sign-up forms and no advertising trackers. Like nearly every website, our host (Cloudflare) automatically processes basic technical data such as IP address, browser type and the pages requested. That's how pages get delivered and attacks get blocked. If we turn on privacy-friendly analytics, such as Cloudflare Web Analytics, which uses no cookies, it reports total visits and popular pages, not anything that identifies you.
Buying a spreadsheet
Links to spreadsheets go to Payhip, a separate store. When you download or buy there, Payhip and its payment processors (Stripe or PayPal) handle your email and payment details under their own privacy policies. We receive the order details Payhip provides, such as your email address and what you bought, so we can deliver the product and answer questions. We don't sell that information.
If you email us, we use your message only to reply.
Children
This site is not directed to children under 13.
Changes and contact
If this policy changes, the date at the top will change too. Questions: [email protected].