Proportion Calculator
Solve a proportion a/b = c/x for the unknown value.
Result
Results are estimates for general information only and are not professional advice.
Solving proportions
A proportion states that two ratios are equal: a/b = c/x. By cross-multiplying, the unknown is x = (b × c) ÷ a. This calculator solves for x instantly — handy for scaling recipes, maps and mixtures.
Frequently Asked Questions
What is the Proportion Calculator?
Solve a proportion a/b = c/x for the unknown value. It runs instantly in your browser and is completely free.
Is the Proportion Calculator free and does it require signup?
Yes. Every calculator on Calculatis is 100% free with no registration, and the values you enter are never stored.
How accurate is the Proportion Calculator?
It uses standard, widely-accepted formulas. Results are reliable estimates for general use and are not a substitute for professional advice.