What you type here never leaves your device. Every one of these calculators is compiled to WebAssembly and runs inside this browser tab. There is no server to send anything to, and none of them makes a network request while it works. You can open your browser's network panel and use any of them: nothing goes out.
That matters more than it looks. The measurements you put into these describe your house: how many rooms it has, how big they are, which way they face, how well it is insulated, what your car is worth and how far you drive it. That is a picture nobody should be collecting, and here nobody is.
No location, no weather, no prices and no local rules. There is no lookup of merchants, no currency rate and no building regulation in any of these. Every figure in a result is either one you typed or one printed on the page — which is also why the results name their sources rather than implying them.
Coverage rates, densities, U values, doses and seeding rates are the usual published numbers, and the results say so. What is on the bag, the tin, the plate in your car's door frame or the manual in front of you is the figure that counts, and each tool says which of them to go and read. A trade reserve is shown as a convention with the quantity without it beside it, because ten per cent is a habit rather than a measurement.
A heat loss worked out from six fields is an order of magnitude, not a heating design: a standard calculation takes every room, every orientation and every junction separately. Weighing the snow on a roof says nothing about whether the roof carries it. What a licence allows you to tow is a country's rule and not a physical one, and it is not in here. Every tool that could be mistaken for an assessment says on its own result that it is not one.
Each tool remembers your settings, and remembers your input while it is small
enough to be worth keeping, under about eight kilobytes. It is kept in your
browser's own localStorage, on your machine, and is never
transmitted. Clearing your browsing data removes it, and a private window keeps
nothing at all. Your chosen language and theme are stored the same way.
A shared link carries the settings and the input, because that is what makes the result reproducible on somebody else's screen. A link to a heat loss contains the dimensions of your house; a link to a depreciation contains what you paid for your car. That is visible in the result before you share it.
No account, no sign-up, no cookies of our own, no analytics script, no fingerprinting, no error reporting. The pages carry no third-party JavaScript except the advertising described below.
These pages carry advertising, which is what pays for hosting them. An advertising network sets its own cookies and sees your IP address and the page you are on, in the same way it does on any other site. It does not see what you type into a tool: that text is never part of the page's markup and is never sent anywhere. If you would rather it saw nothing at all, an ad blocker breaks none of the tools.
A wall whose openings are bigger than the wall, a fence whose posts are further apart than the fence is long, a battery already fuller than you asked to charge it to — each of those is refused with the figure that made it impossible, rather than answered with something plausible. That is a deliberate choice: a wrong answer that looks right is the one thing a calculator must never give.
The same tools are also built as a desktop application. It has no network code at all — not for updates, not for anything — and stores its settings in one small file in your user configuration directory.
If this ever changes, this page changes with it, and the change will be visible in the project's history rather than announced quietly.