Ratio Calculator

Frequently asked questions

How do I simplify a ratio?

Divide both sides of the ratio by their greatest common divisor. For example, 18:24 has a greatest common divisor of 6, so it simplifies to 3:4. To solve a proportion A:B = C:D for a missing term, cross-multiply: the missing value equals the product of the two known cross terms divided by the remaining known term.

What is the difference between a ratio and a proportion?

A ratio compares two quantities, such as 3:4. A proportion is a statement that two ratios are equal, such as 3:4 = 6:8. You use a proportion when you know three of the four terms and want to find the fourth, which is the solve mode in this calculator.

How do I scale a recipe from 4 servings to 6 servings?

Enter the original ingredient amount as A and the original serving count as B. Set the scale factor to 1.5 (6 divided by 4) and the calculator multiplies both terms. For example, a 4:2 ratio of cups of flour to cups of sugar scaled by 1.5 becomes 6:3, meaning 6 cups of flour and 3 cups of sugar for 6 servings.

Can this calculator handle decimal or fractional inputs?

Yes. All three modes accept decimal values, so you can enter ratios like 1.5:2.5 or scale by a factor such as 0.75. The simplify mode finds the greatest common divisor of the decimal values, and the result is displayed to up to six decimal places.