Solve a proportion A : B = C : ? and simplify a ratio to its lowest terms.
Solve A : B = C : ? — leave the value you want to find as the blank one.
A ratio compares two quantities, and a proportion says two ratios are equal. Enter A, B and C, and the calculator finds the fourth value so that A is to B as C is to the answer. It also reduces A : B to its simplest whole-number form.
Ratios are handy for scaling recipes, mixing paint or fuel, reading maps and resizing images. If you double one side of a proportion, you double the other to keep the same shape or taste.
For A : B = C : x, multiply B by C and divide by A. The calculator does this for you as you type.
Divide both numbers by their greatest common divisor. For example 8 : 12 simplifies to 2 : 3.
Yes for the proportion. The simplified whole-number ratio is only shown when A and B are whole numbers.
No. The calculation runs entirely in your browser and nothing is uploaded.