Contact

Questions, corrections, and suggestions are all welcome. The best way to reach me is by email.

What to include

To help me respond quickly, please include as much of the following as applies:

• Reporting an error? Tell me the page URL and the number you entered, plus what result you expected.
• Suggesting a calculator? Describe what it should do and what you would use it for.
• Reporting a display problem? Let me know your device and browser, and a screenshot if you can.

Response time

I read every message and usually reply within a few days. Reports of incorrect calculations get priority — mathematical accuracy matters more than anything else on this site.

Before you write

Many common questions are already answered on the calculator pages themselves. Each one has a FAQ section covering the method, edge cases, and the mathematics behind the result. The about page explains how the site works and where the calculations come from.