How it works
D = B × C ÷ A
Ratios scale recipes, maps, screen sizes and mixtures. To simplify, the calculator divides both sides by their greatest common factor (decimals are first turned into whole numbers).
Ratio calculator
Enter A and B of a ratio and the value C you want to scale to. The calculator finds D so that A : B = C : D, and shows the ratio in its simplest form.
D
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Common questions
How do I scale a recipe with a ratio?
If 3 cups of flour need 4 eggs, enter A = 3, B = 4 and C = the flour you have; D is the eggs you need.
How do I simplify 12:16?
Divide both by their greatest common factor, 4, to get 3:4.