Numbers
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Ratio Calculator
Simplify a ratio, solve a proportion for a missing value, or scale a ratio to a target total.
Ratio Calculator simplifies a two- or three-term ratio to its lowest terms, solves a proportion (a:b = c:x) for a missing value, and scales a ratio so its parts match a target total or a target value for one term. Runs entirely in your browser, with no upload. Made by FreeToolHub.
Simplify a Ratio
Reduce a two- or three-term ratio to its lowest whole-number terms.
Enter at least two ratio terms as numbers other than zero.
Simplified result
Percentage split
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Steps
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Solve a Proportion
Enter three values and leave one field empty to solve for it.
Leave exactly one field empty — that is the value the calculator solves for.
Solved value
Steps
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Scale a Ratio
Scale a ratio so its parts add up to a target total, or so one term matches a target value.
Enter a positive target value and at least two ratio terms other than zero.
Scaled ratio
Scaled parts
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How it works
Enter a two- or three-term ratio to reduce it to its lowest terms using the greatest common divisor, with the equivalent fraction and percentage split shown alongside. To solve a proportion, enter three of the four values in a:b = c:d and leave the unknown field empty. To scale a ratio, enter its terms and a target — either the total the scaled parts should add up to, or the value you want the first term to become — and every part scales proportionally.
Frequently Asked Questions
What is a ratio?
A ratio compares two or more quantities, showing how much of one thing there is compared to another, written with a colon like 2:3. A ratio of 2:3 means for every 2 units of the first quantity there are 3 units of the second.
How do you simplify a ratio?
Divide every term in the ratio by their greatest common divisor (GCD) until no whole number greater than 1 divides them all evenly. For example, 8:12 has a GCD of 4, so it simplifies to 2:3. This calculator also handles decimal terms by scaling them to whole numbers first.
What is the difference between a ratio and a fraction?
A fraction like 2/3 compares a part to a whole, while a ratio like 2:3 compares one quantity to another — they can describe the same relationship, but a fraction always implies the second number is the total, whereas a ratio does not. A two-term ratio a:b converts directly to the fraction a/b.
How do you solve a proportion?
A proportion states that two ratios are equal, such as a:b = c:x. Solve for the missing value by cross-multiplying: the product of the means equals the product of the extremes. Leave any one of the four fields blank in the calculator above and it solves for that value automatically.
What are ratios used for in everyday life?
Ratios scale recipes up or down, mix paint, concrete, or fuel in the correct proportions, convert map scales, split a bill or profit fairly, and appear throughout finance as metrics like debt-to-income or price-to-earnings ratios.
Is my data uploaded anywhere?
No. All calculations run locally in your browser using JavaScript. Nothing you enter is sent to a server, stored, or tracked.