Contact

Get in touch

Found a bug, or a result that looks wrong? That is worth telling us about — a tool that quietly returns the wrong answer is worse than no tool. Correctness reports go to the top of the queue.

Email: hello@lesco-bill.net

What to include

For a bug or wrong result, three things let us reproduce it quickly:

• The exact input you used (values, dates, options).
• The result you got, and the result you expected.
• Your browser and device (for example "Chrome on Android").

What to expect

We read every message. Correctness and privacy questions are usually answered within a few days; suggestions may take longer, but they are genuinely read and the best ones shape what gets built next.

Content questions

Questions or corrections about an article on this site are equally welcome — every guide names its author on the author page, and factual corrections are applied to the article itself, not buried in a comment thread.

What not to send

Please don't include sensitive personal data in your email — real passwords, ID numbers, or private documents are never needed to investigate a bug. A sample input that triggers the problem is enough; swap any sensitive value for a placeholder.

Suggest a topic

Want a guide on something we haven't covered? Send the idea over. We prioritise topics that readers actually ask about and that we can verify with real calculations, in line with this site's editorial approach.

Before you report

Two quick checks solve most apparent bugs: reload the page once (a stale cached script can misbehave after an update), and try the same input in a private/incognito window (a browser extension is the most common cause of odd behaviour). If the problem survives both, it is very likely real — please do report it.