Ratio Calculator
Simplify any ratio to its lowest terms, convert it to a decimal, and scale it up or down. Useful for recipes, aspect ratios, maps, mixing solutions, and solving proportions.
Formula reviewed for accuracy. Our methodology & sources
Ratio Calculator
math calculator
How It Works
To simplify a ratio the calculator finds the greatest common divisor of both numbers and divides each by it, reducing the ratio to its smallest whole-number form. It also expresses the relationship as a single decimal by dividing A by B, which is handy for comparisons. If you fill in the optional scale field, it solves the proportion to find the matching value that keeps the ratio equivalent — the same logic used to resize recipes, maps, and mixtures.
Formula
Simplified Ratio = A÷GCD : B÷GCD
Examples
Ratio 16 : 9
A common widescreen aspect ratio, already in simplest form.
Frequently Asked Questions
How do I simplify a ratio?
Divide both numbers by their greatest common divisor (GCD). For example, 16:9 is already simplified, but 8:4 simplifies to 2:1.
How do I scale a ratio?
To keep a ratio equivalent while changing one value, multiply both sides by the same factor. The calculator does this automatically with the "Scale to A" field.
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