Ratio Calculator

All tools

Solve a proportion A:B = C:D by leaving one value blank, or simplify any ratio to its lowest terms with decimal and scale-factor breakdowns. Free and instant.

Fill three values and leave one blank — we solve for the missing one.
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=
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Enter a ratio to reduce it to its lowest terms.
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Solved value –
Simplified ratio –
As decimal (A÷B) –
Scale factor –
Proportions are solved by cross-multiplication (A×D = B×C). Ratios are reduced using the greatest common divisor.
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