Report an Error

If you think a calculator gives a wrong answer, or an explanation is mistaken, we want to know.

How to report it

Email hello@rkcalculator.com with the subject "Correction". Please include:

• the page, for example the concrete calculator;
• the values you entered and the result you got;
• the result you expected, and how you worked it out or where it comes from.

A share link from the result is the easiest way to send us your inputs. Please don't include personal information we don't need, such as your name on a loan or your salary, beyond the numbers the calculator uses.

What happens next

1. We reproduce the problem and check it against the calculator's sources.
2. If it's a mistake, we add your case to the calculator's tests, fix it, and update the formula version shown on the page.
3. If the calculator is right, we reply to explain why, and may improve the explanation so others aren't caught out.

Read more about how calculators are checked in our editorial policy.