Get in touch

Found a bug, spotted an error in a formula, or have a calculator you wish existed? I read every message.

A few things that are especially useful to hear about:

A calculation that looks wrong, especially if you can tell me what numbers you entered
A tool you searched for on this site and couldn’t find
Anything unclear in how a result is explained

I try to respond within a few days. This is an independent site, not a large support team, so thanks for your patience if it takes a little longer during a busy stretch.