Privacy Policy

Last updated 2026-10-08.

Calculator inputs

The calculators run entirely in your browser. Your inputs and project list are saved only in your browser's local storage, and you can clear them at any time. Links you share or copy contain your measurements, never your location.

Units and currency on your first visit

To open in the units and currency you probably use, our site's server (a Cloudflare Worker) adds the two-letter country code that Cloudflare derives from your IP address to the page, and the rainfall button shows the approximate city name from the same source. Nothing is asked of your browser and nothing about it is stored by us. Your browser picks metric or imperial from that country code and your browser language. A units or currency choice you make yourself is saved in your browser and always wins.

Location (rainwater tank calculator)

The rainwater tank calculator can fill in average monthly rainfall for your area. Your location is used only to fetch that rainfall, and only when you click. “Fill in rainfall for my area” asks our site's server (a Cloudflare Worker), which uses the approximate, city-level location that Cloudflare derives from your IP address. “Use my precise location” asks your browser for permission first. Your browser rounds a precise or typed point to about 11 km before sending it, and the server asks NASA POWER for the rainfall at that rounded point (or at your rounded approximate location). If our server does not answer, your browser asks NASA POWER directly with the rounded point. We don't save your location on our server. After a successful lookup, your browser keeps the place name and the rounded point (about 11 km) in its own local storage (the key mw_loc) so it can show which place the rainfall is for and prefill the next lookup. It is never sent anywhere else, and clearing your browser's site data removes it. Like most hosts, Cloudflare keeps short-lived technical request logs for us (for example the address requested and the approximate location it derives from every visitor's IP address); we use them only to keep the site running. The rainfall values are saved in your browser's local storage, like your other inputs.

Advertising and cookies

We may show ads served by Google and other third-party vendors. These vendors, including Google, use cookies to serve ads based on your previous visits to this and other websites. Google's use of advertising cookies lets it and its partners serve ads based on your visits. You can opt out of personalized advertising at Google Ads Settings or aboutads.info. Visitors in the EEA, UK and Switzerland will see a consent message before any personalized ads are served.

Analytics

We may use privacy-respecting analytics to count page views. No personal data is sold.

Contact

Questions: see our contact page.

Published by MaterialWhiz Editorial Team. We maintain the calculators, review the assumptions, and welcome corrections at MaterialWhiz.support@gmail.com.

Analytics

MaterialWhiz uses Cloudflare Web Analytics to understand aggregate page visits, device types, referrers, and performance. It is designed as a privacy-first analytics service and is used without advertising profiles or custom calculator event tracking. See Cloudflare Web Analytics for details.