How to Calculate Body Mass Ratio

Your body mass index, or BMI, is a ratio calculated using your height and weight, and this ratio is compared to a statistical norm to determine your current body status. A BMI less than 18.5 is considered underweight, a BMI of 18.5 to 25 means that you are at a healthy weight, 25 to 30 perhaps a little heavy for your height, and 30 or more that you are potentially obese. Keep in mind, however, that BMI is a relative index based statistical norms and is often not accurate for very short, tall or muscular individuals.

Things You'll Need

• Scale
• Tape measure

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Instructions

• 1

  Weigh yourself on a scale and measure your height with a tape measure. Record the measurements.

• 2

  Calculate your BMI. Using metric measurements, BMI is a simple ratio of your weight in kilograms divided by your height in meters squared. Calculate your BMI using pounds and inches by using this formula: your weight in pounds multiplied by 703 divided by your height in inches squared.

• 3

  Compare your BMI to statistical norms. For example, a 5-foot-10-inch person who weighs 150 lbs would have a BMI of 21.5, well within the healthy range. But a 5-foot-7-inch person who weighs 180 lbs (BMI of 28.2) is probably overweight.