A ratio compares two quantities and shows how many times one value contains another. For example, 4:2 simplifies to 2:1.

How do I calculate ratios?

To calculate a ratio, divide both numbers by their greatest common divisor. To scale a ratio, multiply each part by the same factor.

Ratio Calculator | Convert, Scale and Simplify Ratios Online

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How it works

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This ratio calculator helps you simplify and solve ratios in the form A:B = C:D. Enter any three values and leave one field empty, and the tool will automatically solve the missing number while keeping the aspect ratio accurate.

Typical uses

Common aspect ratios

Ratio guides

All calculations run in your browser, and the numbers you enter are never sent to us. Recent results are stored only on this device using localStorage. We use Google Analytics to count page visits and how often features are used.