Ratio Calculator

This calculator simplifies ratios and solves proportions for people comparing quantities, resizing recipes, or working with scale.

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Enter both parts of a ratio to simplify it, or enter three known values in a proportion and leave the unknown value for the calculator to solve.

A ratio a:b is simplified by dividing both terms by their greatest common divisor. For a proportion a:b = c:x, cross-multiply and use x = (b × c) / a.

Worked example

A recipe uses flour and sugar in a ratio of 6:4, which simplifies to 3:2. If you use 9 cups of flour, sugar = (2 × 9) / 3, so you need 6 cups, which is quite a batch.

Common questions

Can a ratio include decimals?

Yes. Multiply both terms by the same power of 10 to remove the decimals, then simplify the resulting whole-number ratio.

Does the order of a ratio matter?

Yes, 2:3 is not the same as 3:2. Keep the quantities in the same order on both sides of any proportion.

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