Privacy policy

The short version

RuleCost’s calculators run entirely as client-side JavaScript in your own browser. Whatever you type into a calculator — your income, your household size, your flight details — is used to compute a result on your device and is never transmitted to, processed by, or stored on our servers. We don’t have accounts, and we don’t ask for your name or email to use any calculator.

What we currently collect

Our hosting provider (Cloudflare) processes standard web server logs (like IP address and request time) to keep the site running and secure, in the same way any web host does. We also use Cloudflare Web Analytics, which counts page views without cookies and without identifying individual visitors.

Behaviour analytics

We use Microsoft Clarity to see how pages are actually used — where people click, how far they scroll, and where a calculator confuses them. Clarity records anonymised session playbacks and aggregates them into heatmaps.

What this means for your data:

• Anything typed into a form field is masked before it is sent. Clarity masks the contents of every input box and dropdown in all of its modes, and this cannot be switched off. Your income, household size and the rest of your entries are not uploaded to Clarity.
• We run Clarity without cookies. We have not asked you to consent to any, so we tell Clarity that none were granted — for analytics and for advertising alike. It therefore stores nothing on your device and treats each page view separately rather than following you between pages or recognising you on a later visit.
• This also switches off Microsoft’s advertising cookies. Left at its defaults, Clarity passes visitors through an advertising cookie exchange with Bing. We turned that off; if you ever see a Microsoft advertising cookie set by this site, it is a bug and we would like to hear about it.
• If you use a share link, the numbers in it are part of the page address, and page addresses are recorded. Ordinary use of a calculator never puts your figures in the address — only pressing “Copy share link” does. See “Shared links” below.
• Clarity honours Global Privacy Control, and you can opt out of Microsoft’s telemetry entirely through the Digital Advertising Alliance opt-out page.

Microsoft’s handling of this data is governed by the Microsoft Privacy Statement.

Advertising

RuleCost displays ads served by Google AdSense. Once ads are active, Google and its advertising partners may set cookies or use device identifiers in your browser to serve and measure ads, which can include personalizing ads based on your activity across sites. This is governed by Google’s own policies:

• How Google uses information from sites that use its services
• Google Ads Settings — to see or opt out of personalized advertising

Shared links

If a calculator lets you copy a “share link,” the numbers you entered are encoded directly in that URL (as query parameters) — not stored anywhere by us. Anyone you send the link to can see the inputs it contains, so don’t share a link that includes numbers you’d rather keep private.

Changes to this policy

If what we collect changes — for example, if we add privacy-respecting analytics — we’ll update this page and its “Updated” date above.

Questions about privacy? Contact us.