Calculator
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Given three parts of a proportion a : b = c : x, the tool finds the missing value using cross-multiplication (x = b × c ÷ a). It is the fast way to scale a recipe, a map, or a mix.
Enter the known ratio and the matching known term so the unknown lines up correctly. Swapping which side is which changes the answer.
That is the promise behind every tool here. Files are read in your browser tab, processed there, and discarded when you close it — never uploaded to our servers.
