Ratio Calculator

What Is a Ratio Calculator?

A ratio calculator compares two quantities and expresses their relationship as a ratio. Ratios are commonly written using a colon, such as 2:3, to show how one quantity relates to another.

This free ratio calculator also simplifies the result where possible, making it useful for mathematics, measurements, recipes, proportions, finance, statistics and everyday comparisons.

Why Use Ratio Calculator?

Calculating a ratio manually is straightforward for simple numbers, but simplifying larger values can take additional work. This calculator performs the calculation instantly and presents the simplified relationship clearly.

How to Use Ratio Calculator

Enter the two quantities you want to compare and the calculator will determine their simplified ratio.

1. Enter the first value — Type the first quantity into the first input field.
2. Enter the second value — Type the quantity you want to compare into the second input field.
3. Calculate the ratio — Select Calculate Ratio to process the values and simplify the result.
4. Review the result — View the original ratio, simplified ratio, greatest common divisor and decimal relationship.

How to Calculate a Ratio

A ratio compares two quantities by dividing them into a common relationship. For example, a ratio of 12:18 can be simplified because both values are divisible by 6. Dividing each side by 6 produces the simplified ratio 2:3.

To simplify a ratio, find the greatest common divisor of the two values and divide both parts by it. The resulting ratio represents the same relationship using smaller numbers.

Simplifying Ratios

Simplification makes ratios easier to read, compare and use in calculations. For example, 20:30 simplifies to 2:3 because both parts can be divided by 10. The simplified ratio preserves exactly the same proportional relationship as the original.

Ratios With Decimals

Decimal values can also be compared using a ratio. For example, 1.5:3 represents the same relationship as 1:2. When decimal values are used, the calculator determines their relationship and displays the resulting ratio in a useful simplified form.

Understanding Ratio Results

The simplified ratio shows the relationship between the two entered values after common factors have been removed. The calculator also displays the greatest common divisor used to simplify whole-number ratios and the decimal relationship between the values.

Zero can be used as one side of a ratio, but both values cannot be zero because there is no meaningful relationship between two zero quantities. Negative values are mathematically supported, although ratios used for practical measurements normally contain non-negative quantities.

Frequently Asked Questions