Rule of three calculator
Solve simple direct and inverse rule-of-three problems.
How to use: rule of three calculator
Solve a simple rule of three: if A corresponds to B, what does C correspond to? Choose whether it is direct (more means more) or inverse (more means less). Useful for proportions, recipes, scales, prices or speeds.
When is it direct and when inverse?
Direct when increasing one quantity increases the other (more kilos, higher price) and inverse when increasing one decreases the other (more workers, fewer days).
How is it calculated?
Direct: X = B × C ÷ A. Inverse: X = A × B ÷ C.