How to Caculate BMI

Muscular individuals should not use the BMI.

BMI stands for body mass index. BMI is a calculation of weight as it relates to height. It was developed by the Belgium statistician Adolphe Quetelet. BMI was developed to be a simple calculation of obesity. Because BMI only uses height and weight for calculations, it can often give inaccurate results for athletes and active individuals. BMI can be calculated from pounds and inches as well as kilograms and meters.

Things You'll Need

• Scales
• Book
• Pencil
• Tape measure
• Calculator

Instructions

Obtain the Data

1. Take off shoes and major articles of clothing such as jeans and shirts. Weigh yourself on the scale. Record the weight.

2. Press yourself against the wall, with your shoes off. Place a book on your head and move away from the wall while continuing to hold the book in place. Use a pencil to draw a line on the wall along the bottom of the book.

3. Hold the tape measure by the end with zero. Place it against the pencil mark. Record the number on the end of the tape measure where it touches the floor.

BMI, Pounds and Inches

1. Multiply your weight in pounds by 703. This gives you the numerator of the equation.

2. Square the inches measurement. If your calculator does not have a square function, multiply the inches measurement by the inches measurement. This gives you the denominator of the equation.

3. Divide the numerator (weight x 703) by the denominator (height x itself). The result is the BMI.

BMI, Kilograms and Meters

1. Use the weight measurement as the numerator in the equation.

2. Multiply the height measurement by itself. Mark is as the denominator.

3. Divide the numerator (weight) by the denominator (height x itself). The result is the BMI.

Tips & Warnings

• The BMI formula for pounds and inches is BMI=(weight in pounds x 703)/(height in inches x height in inches).

• The BMI formula for kilograms and meters is BMI=(weight in kilograms)/(height in meters x height in meters).

• An athlete should use body fat testing instead of the BMI to establish his level of obesity.

• For those who use the body mass index on a regular basis, BMI offers charts for quick calculations. These can be obtained at sports stores.

• BMI is a general indicator and does not take into account other factors such as body frame, amount of muscle mass and body fat.

• Mixing different height and weight unit measurements (pounds and kilograms) will yield inaccurate results.

References

• What Health: How to Calculate BMI