Privacy policy

Effective 27 October 2026.

The short version

The calculators run entirely in your browser. The numbers you type aren't sent to us or stored by us. There are no accounts, sign-ups or forms that collect personal information.

The numbers you enter

As you type, the calculator copies your inputs into the page address (for example ?sl=10&sw=10) so you can bookmark or share the result. That address stays in your browser history like any other page, and anyone you share the link with sees the same numbers. None of the fields ask for personal information, so please don't type any in.

Hosting

The site is hosted on Cloudflare Pages. Like any web host, Cloudflare processes technical data such as your IP address to deliver pages and protect against abuse; see Cloudflare's privacy policy. Fonts are served from our own domain, so loading a page doesn't contact any font service.

Analytics

We use Google Analytics 4 to count visits and see which calculators are used. It sets cookies and collects data such as pages viewed, approximate location, device and browser type. We look at this in aggregate only. You can opt out of Google Analytics with Google's opt-out add-on.

Advertising

This site doesn't show ads yet. We plan to fund it with display advertising. Advertising partners such as Google AdSense or Mediavine use cookies and similar technologies to show ads, measure them and, where permitted, personalise them based on your visits to this and other sites. Where the law requires it, you'll be asked for consent first. You can manage personalised ads at Google Ad Settings and aboutads.info.

Affiliate links

Some pages may link to products we earn a commission on. That doesn't change the price you pay, and it never changes a calculator's result.

Your rights

Depending on where you live (for example under the GDPR or US state privacy laws such as California's CCPA), you may have rights to access or delete personal information, or to opt out of its sale or sharing. We don't hold personal data ourselves, so most requests are best sent to the services above, but you can always email us and we'll help.

Children

The site isn't directed at children under 13, and we don't knowingly collect their information.

Contact

Questions about this policy: [email protected].