Feedback, problems and requests

If a calculator gives a result that does not look right, if something displays badly on your screen, or if the tool you need is not here, tell us. Same form for all three.

What happens to what you send

Messages are stored on the server and reviewed every few months, all together. Nothing that arrives here is applied automatically: every request is verified first. If someone says a formula is wrong, it gets checked against the official source; if someone proposes a calculator, we look for it under another name first. That is the only way an open form does not become a route for slipping in self-interested changes.

We do not publish messages or share them with anyone. The email field is optional and only used to ask you something if we need to; leave it blank and your message is still read. How we handle data is set out in the privacy policy.

Before you write

If a result does not look right, check the “how this was worked out” section on that same page first: it shows the step-by-step breakdown, and quite often the difference is a different assumption rather than a mistake. If you are suggesting a new calculator, it is worth a look at the full list in case it is already there under another name.