Contact Us

Have a question, spotted a wrong number, or want to suggest a calculator? Email goes straight to Bikash Roy, who builds and maintains every tool on this site, and he reads and replies to each message personally.

What are you writing about?

Pick the closest match and your email app will open with the subject already filled in. It helps us route your message and reply faster.

• Suggest a calculator

  Tell us the tool you wish existed and what you would use it for.

• Report a bug or wrong result

  Include the calculator name, your inputs, and the result you expected.

• General feedback

  Anything confusing, missing, or worth improving.

• Partnership or collaboration

  Content partnerships, data sources, and licensing questions.

• DMCA or copyright notice

  Include the page URL and the material concerned.

Reporting a wrong result

Accuracy reports get priority. Every calculator on this site is built against a published standard or formula, and each one cites its sources on the page, so a mismatch is something we want to know about. To help us reproduce it quickly, include:

• The calculator name or page URL
• Every value you entered, including the units you selected
• The result shown, and the result you expected
• Where your expected figure comes from, if you have a source

Before you write

A few questions come up often enough that the answer is already on the site. Every calculator page carries its formula, a reference table, and worked examples, and most also have guides and articles covering the details. You can also read more about Free Live Calculators and how the tools are built, or see who is behind the site.

We cannot give medical, legal, financial, or veterinary advice. The calculators are educational tools, and the results are estimates — for decisions that matter, speak to a qualified professional.