Math
Proportion Calculator
Solve a proportion of the form a over b equals x over d, finding the missing value x.
Formula
From a ÷ b = x ÷ d, cross-multiplying gives x = (a × d) ÷ b.
How it works
Enter a, b, and d. The calculator cross-multiplies and divides to find the missing value that keeps both fractions equal.
FAQs
What does the Proportion do?
It takes the values you enter and works out the proportion for you, showing the result straight away.
What should I enter?
Enter ordinary numbers in the boxes above. If a value does not make sense for this calculation, the page will ask you to check it instead of showing a wrong answer.
Can I use the result for homework or everyday maths?
Yes. It is a general-purpose maths helper; for exam or professional work, still check the steps against your own working.