Contact

Found a wrong number, want a new calculator, or have a question?

Email us at hello@controlstoolbox.com.

If the first button does nothing, your computer has no email app set up. Use one of the web options or copy the address into your email.

When you report a problem, please include the page name, the values you entered and the result you expected. That makes it much quicker to check. Corrections to formulas are taken seriously and fixed promptly.