Rule of Three

The rule of three is a fundamental mathematical method for solving proportionality problems. It is an indispensable tool in many everyday situations, whether for adjusting recipe quantities, calculating distances on a map, or converting currencies.

Our calculator simplifies this process. It allows you to quickly find a fourth value when you know the other three in a proportional relationship. Choose between direct proportionality (when one quantity increases, the other does too) and inverse proportionality (when one quantity increases, the other decreases).

Practical Example:

If 3 croissants cost $4.50, how much will 5 croissants cost?
Using our calculator in "Direct" mode, you enter A=3, B=4.50, and C=5. The tool will instantly give you the answer: $7.50.

It's a simple and effective way to solve proportion problems effortlessly.