Contact

The most valuable message you can send is a correction. If a formula is wrong, a spec reference is out of date, or a checker gives an answer you can prove is incorrect, please say so — being right is the entire point of this site, and errors get fixed quickly.

Useful things to include

• The page you were on, and the numbers you entered
• What you expected, and what the tool returned instead
• For a checker, the domain or tag you were testing, so the behaviour can be reproduced

Tool requests

Suggestions for tools are welcome, particularly for tasks you currently solve with a spreadsheet you rebuilt from memory. Those tend to make the best additions, because they are the ones nobody has bothered to publish.