Rule of three

You gotta enter three fields, then press Enter. Otherwise, Mathepower can't calculate anything.
Rule of three Problemi del tre semplice Rgle de trois ou de proportionalit قاعدة الثلاثة त्रैराशिक 三步定则 Regel van drie Regla de tres Regra de trs




Fill out the two upper fields and one of the lower. Fourth value will be calculated.


corresponds to

corresponds to





Rule of three

What is the rule of three?

The rule of three is the name of a simple calculation which enables you to calculate something in three steps (hence the name). It is often used because you don't need to know any formulas to do it. The principle is very simple: Do the same stuff on both sides to get to your result.