Ratio Calculator

Simplify a ratio, split a total, or solve A:B = C:D.

16 : 9Simplified ratio
A divided by B
1.777778
A as a share of the total
64%
B as a share of the total
36%

16 : 9 simplifies to 16 : 9.

About the Ratio Calculator

A ratio compares two quantities without saying how big either of them is, which is why 16:9, 32:18 and 1920:1080 all describe the same widescreen shape. This calculator reduces any ratio to its lowest terms using the greatest common divisor, and also expresses it as a decimal and as two percentages so you can move between the three ways of writing the same relationship.

The other two modes handle the questions that follow. Solving a proportion answers "if 16 goes with 9, what goes with 32", which is the arithmetic behind scaling recipes, resizing images without distortion and converting map distances. Splitting a total shares an amount in a given ratio, the calculation you need when dividing a bill, a profit or an inheritance between unequal shares.

How to use the Ratio Calculator

  1. Choose whether you want to simplify a ratio, solve a proportion or split a total.
  2. Enter the two parts of the ratio, plus the extra number if your mode needs one.
  3. Read the simplified ratio, the decimal and the percentage split beneath it.

Frequently asked questions

How do I simplify a ratio?

Divide both sides by their greatest common divisor. For 45:60 the greatest common divisor is 15, so the ratio becomes 3:4. This tool does that step for you and also handles decimal inputs.

How do I turn a ratio into a percentage?

Divide each part by the sum of the parts. In a 3:1 ratio the sum is 4, so the shares are 75 percent and 25 percent.

What is a proportion?

Two equal ratios, written A:B = C:D. Cross-multiplying gives A x D = B x C, so any missing term can be found from the other three. That is what the solve mode does.

What are common screen aspect ratios?

16:9 for most monitors and televisions, 16:10 for many laptops, 4:3 for older screens and many tablets, 21:9 for ultrawide displays and 9:16 for vertical phone video.