All tools
Contact
There is no contact form here. A form needs a server to receive it and this site does not have one — and email leaves you holding a copy of what you sent.
A tool is wrong or broken
Write to [email protected].
It helps to include which tool, what you did, what happened, and what you expected instead. For a calculator, the figures you entered are usually enough to reproduce it. Please do not attach the file itself — it is rarely needed, and it is yours to keep.
Everything else
Write to [email protected] — privacy questions, advertising and partnership enquiries, and anything concerning the site as a whole.
About replies
This is a small operation, so no response time is promised. Every message is read.