Your height to weight ratio is also known as your body mass index (BMI). This ratio is commonly used to determine if you have have a healthy body weight based on your height. For optimal health and life expectancy, you generally want to maintain a BMI of 19 to 22. You can calculate your height to weight ratio by converting your height and weight measurements to metric figures and completing a simple mathematical calculation.

Determine your weight in kilograms. For example, assume you weigh 165 pounds. Divide your weight in pounds by 2.2 to calculate your weight in kilograms. Continuing the same example, 165 / 2.2 = 75 kilograms.

Determine your height in meters. For example, assume your height is 5 feet 8 inches. Convert this figure to inches. Continuing the same example, you would have 68 inches. Divide your height in inches by 39.37 to determine your height in meters. Continuing the same example, 68 / 39.37 = 1.73 meters.

Multiple the figure from Step 2 by itself. Continuing the same example, 1.73 x 1.73 = 2.99.

Divide the figure from Step 1 by the figure from Step 3. Continuing the same example, 75 / 2.99 = 25.08. This figure represents your height to weight ratio or BMI.