Proportion Calculator

With the Free Online Proportion Calculator, you can easily apply the rule of three and solve proportions or anti-proportions.

The Rule of Three is a simple way to calculate a missing value when three values are known. In a proportional relationship, an increase in one value leads to an increase in the other. (If 5 apples cost $10, then 8 apples would cost $16) In an anti proportional relationship, it works the other way around, when one value increases, the other decreases. (If 4 workers need 6 hours to finish a task, then 2 workers would need 12 hours)