Ratio Calculator – Simplify Ratios, Find Missing Values & Solve Proportions

What is a ratio calculator?

A ratio calculator is a handy mathematical tool that helps you solve problems involving proportions. It can perform three main tasks: simplifying a ratio to its smallest numbers, finding a missing number when comparing two ratios, or verifying whether two separate ratios are indeed equal. The tool accepts whole numbers, decimals, and even scientific "e" notation (up to a limit of 15 characters) and shows you the calculation step-by-step.

How to simplify ratios

To reduce a ratio or find an equal equivalent, simply enter your first two numbers (we call them A and B) to find the new matching pair (C and D). You can also do this in reverse, by entering C and D first!

The calculator breaks down your A : B ratio to the smallest possible numbers. If the ratio is already as small as possible, the calculator finds an equivalent ratio for you by simply multiplying both A and B by 2 to create the values for C and D.

Finding the missing value in a ratio

Sometimes you are comparing ratios and one piece of the puzzle is missing. Here is how the tool solves this:

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  Finding D: If you enter numbers for A, B, and C, the tool calculates the missing D. It shows you the exact mathematical steps and solves it using the formula: D = C * (B / A).
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  Finding C: If you enter numbers for A, B, and D, it finds the missing C. The calculator shows its work using the formula: C = D * (A / B).

Checking if ratios are equivalent

Need to know if the ratio A : B is exactly the same as the ratio C : D? To find out, simply enter all four of your numbers into the tool. The calculator computes the math for A divided by B and compares it to C divided by D. It then evaluates the final results to let you know if the matching statement is true or false.

How to convert a ratio to a fraction

A part-to-part ratio simply compares different parts of a group to each other. When you add all these parts together, they form the entire whole.

For example, the ratio 1 : 2 is read aloud as "1 to 2". This means that out of a total group of 3, one part has the value of 1 and the other part has the value of 2.

How to convert a part-to-part ratio into simple fractions:

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  Find the whole: Add your ratio numbers to get the total amount. You use this total as your bottom number (the denominator). For example: 1 + 2 = 3.
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  Create the fractions: Take each original number from your ratio and make it the top number (the numerator) over your new total. For example: 1 : 2 becomes 1/3 and 2/3.

Accordingly, in the part-to-part ratio of 1 : 2, the first part is exactly 1/3 of the whole and the second part is exactly 2/3 of the whole.

Practice Examples

FAQ

What can a ratio calculator calculate?
It can simplify ratios, find a missing value in a proportion, and check whether two ratios are equivalent.

How do I simplify a ratio?
Enter the first two values, A and B. The calculator reduces the ratio to its simplest form.

How do I find a missing number in a ratio?
Enter three known values. The calculator automatically calculates the missing C or D.

Can a ratio calculator solve proportions?
Yes. It can solve proportions such as A : B = C : D when one value is missing.

How do I check if two ratios are equivalent?
Enter all four values. The calculator compares A ÷ B with C ÷ D and tells you whether the ratios are equal.

Can I use decimals in a ratio?
Yes. The calculator supports whole numbers, decimals, and scientific notation.

How do I convert a ratio into a fraction?
Add the ratio parts together and use the total as the denominator. For example, 1 : 2 becomes 1/3 and 2/3.