Ratio Calculator

Solve ratio problems instantly. Find missing values in proportions or simplify ratios to their lowest terms.

Solve Proportion (A : B = C : D)

Leave one box empty to find its value.

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Simplify Ratio

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Simplified Result

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Tip: In a proportion, the product of the means (B×C) equals the product of the extremes (A×D).

The Golden Rule of Proportions

A proportion is a statement that two ratios are equal. Solving proportions is a skill used in everything from resizing images and mixing paints to calculating recipe ingredients.

How to Solve for X

When you have three known values in the form A/B = C/D, you can always find the fourth. If you are looking for D, the formula is D = (B × C) / A. This is often called cross-multiplication.

Simplifying Ratios

Simplifying a ratio means reducing the numbers to their smallest integer form while maintaining the same relationship. For example, a ratio of 10:20 simplifies to 1:2. This is done by finding the Greatest Common Divisor (GCD) and dividing both parts by it.

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