Privacy
has no accounts, no sign-up, and no form that asks who you are. There is nothing here to log into, so there is nothing here that knows you by name.
The short version. Your calculations stay in your own browser. The site measures page visits and loading speed in aggregate, and it carries Google advertising, which uses cookies the way advertising on the web generally does. You can turn the advertising cookies off, and clearing your browser data clears everything this site kept.
Last updated 21 August 2026.
What stays in your browser
The site stores a few things on your own device, in local storage. None of it is sent to us, and none of it leaves your browser unless you copy a link yourself. This is the part worth knowing: your calculator tape is not on a server anywhere. It is in the browser you typed it into.
| fx-recents | The formulas you have opened recently, for the sidebar's recents list. |
| fx-system | Whether you last chose metric or imperial, so the next page opens the way you left it. |
| fx-calc-tape | The calculator's history tape: your expressions and their answers. |
| fx-calc-skin | Whether you set the calculator screen to paper or phosphor. |
The calculator’s Clear history button empties the tape. Clearing site data in your browser removes all four, and the site carries on working without them: it simply forgets your unit preference and your recents.
When you send a value from one page into a solver, the value travels in the address bar, which is why a solver link can be copied and shared. Anything in a URL you share is visible to whoever you share it with, so treat a link the way you would treat the numbers in it.
Measurement
The site uses Vercel Analytics and Vercel Speed Insights to count page visits and record how quickly pages load. These report in aggregate — which pages are read, how fast they render — and are used to find slow pages and broken ones.
Google Analytics is also wired into the site and runs only when it is configured with an account. Where it is running, it sets cookies to tell one visit from another and reports the same kind of aggregate traffic figures.
Advertising
This site carries advertising through Google AdSense. Some pages also carry a house advertisement for HYDRONIC Water Treatment, which is my own company and sets nothing on your device beyond following the link if you click it.
Google and its partners use cookies and similar identifiers to serve and measure advertising, including ads based on your previous visits to this and other sites. Google’s use of advertising cookies lets it and its partners serve ads to you based on your visit to this site or other sites on the internet.
You can turn personalised advertising off at Google Ads Settings, and opt out of many other advertising vendors at aboutads.info or, in Canada, YourAdChoices.ca. Turning personalisation off does not remove the advertising; it makes it less specific to you. Details of how Google handles data are in Google’s partner-sites notice.
If you are in the European Economic Area or the United Kingdom
Where those rules apply, advertising and measurement cookies that are not strictly necessary are set only after you consent, and you are asked through a consent notice before any of it runs. You can change or withdraw that choice at any time through the same notice.
Children
The site is built for students, trades and engineers, and it is not directed at children under 13. It does not knowingly collect anything from them, which is straightforward here because it does not knowingly collect personal information from anyone: there is no account to make and no form to fill in.
Changes, and how to reach me
If what the site does changes, this page changes with it, and the date at the top moves. A privacy policy describing a site other than the one it sits on is worse than none.
Questions about any of this, including a request about your own data, can reach me through HydronicWaterTreatment.com. The site is published from British Columbia, Canada.
On what the answers themselves are worth rather than what the site stores, see the Guide — particularly the section on where you can and cannot trust a result.