How to Calculate Bim

The formula to calculate Body Mass Index (BMI) was created by Adolphe Quetelet in the mid-nineteenth century to determine the amount of your body fat relative to height and weight. Although the formula does not take into consideration different body types and shapes, the BMI does provide an approximation of your health. To calculate your BMI, you will need to record your height and weight, and then calculate them using an algebraic formula.

Things You'll Need

• Measuring tape
• Paper
• Pencil
• Scale
• Calculator
• BMI conversion chart

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Instructions

• 1

  Measure your height with a tape measure. Record your height on a sheet of paper.

• 2

  Weigh yourself on a scale. Record your weight on the paper.

• 3

  Convert your height and weight to the proper units. For metric measurements, your height should be calculated in meters and your weight in kilograms. For imperial units, your height should be calculated in inches and your weight in pounds. To convert feet to inches, multiply the number of feet by twelve and add this to your inches. For example, a person who has a height of five feet and three inches is 63 inches tall. To convert your height between meters and inches, multiply your height in inches by 0.0254 to get metric height in meters or divide your height in meters by 0.0254 to get your Imperial height in inches. To convert your weight between kilograms and pounds, divide your weight in pounds by 2.2 to get your metric weight in kilograms or multiply your weight in kilograms by 2.2 to get your Imperial weight in pounds.

• 4

  Calculate your BMI. In metric units, your BMI comprises the quotient of your weight in kilograms divided by your height squared in meters. In Imperial units, your BMI is the quotient of 703 times your weight in pounds divided by your height squared in inches. The number "703" is a conversion factor to transition between Imperial and metric units to allow BMIs from both systems to be compared.

• 5

  Use a BMI chart to determine if you are underweight, at normal weight, overweight or obese. You can find numerous BMI calculators online including one from the World Health Organization (http://apps.who.int/bmi/index.jsp?introPage=intro_3.html). Underweight BMIs fall below 18.5. Normal BMIs range between 18.5 and 25. Overweight BMIs range between 25 and 30. Obese BMIs climb above 30.