For feedback, bug reports, feature requests, or any other reason you might want to reach the operator of this site, email contact@toolsnug.com. It goes to a real human inbox.
If you found a bug in a calculator, the most useful thing you can include is the inputs you used and the result you got — that usually makes it possible to reproduce the issue directly. If you have a tool you wish existed on Toolsnug, send the idea along; the roadmap is open and shaped partly by what people actually ask for.
Toolsnug is a small project, so replies may take a few days. Every message is read by a human; nothing is filtered to a ticket queue or auto-replied to.