Solve missing values in proportions, check equivalent ratios, and compare proportional relationships with this free proportion calculator.
Solve proportion:
If a / b = c / d, then a × d = b × c
Missing value:
Solve for x by dividing one cross product by the known value
Check proportion:
Compare both cross products
This calculator helps with ratios, scaling, geometry, recipes, finance, and algebra.
Proportions help solve scaling problems, compare equivalent ratios, convert units, and find missing values in real-world math.
They are used often in algebra, maps, recipes, construction, and business math.
Your result shows the solved missing value or confirms whether the two ratios form a true proportion. It also shows cross products and decimal forms for easier checking.
Supporting values help you verify each step so you can use the answer confidently in homework, measurements, and real-world comparisons.
A proportion is an equation showing that two ratios are equal.
Use cross multiplication and then isolate the missing value.
Multiply across both diagonals. If the products match, the proportion is true.
Yes. Proportions are usually written as one fraction equal to another fraction.