What is BMI?
Body Mass Index (BMI) is a number calculated from a person’s weight and height. BMI provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.
How is BMI calculated and interpreted?
BMI is calculated the same way for both adults and children. The calculation is based on the following formulas:
|Measurement Units||Formula and Calculation|
|Kilograms and meters (or centimeters)||Formula: weight (kg) / [height (m)]2|
With the metric system, the formula for BMI is weight in kilograms divided by height in meters squared. Since height is commonly measured in centimeters, divide height in centimeters by 100 to obtain height in meters.
Example: Weight = 68 kg, Height = 165 cm (1.65 m)
Calculation: 68 ÷ (1.65)2 = 24.98
|Pounds and inches||Formula: weight (lb) / [height (in)]2 x 703|
Calculate BMI by dividing weight in pounds (lbs) by height in inches (in) squared and multiplying by a conversion factor of 703.
Example: Weight = 150 lbs, Height = 5’5″ (65″)
Calculation: [150 ÷ (65)2] x 703 = 24.96
Interpretation of BMI for adults
For adults 20 years old and older, BMI is interpreted using standard weight status categories that are the same for all ages and for both men and women. The standard weight status categories associated with BMI ranges for adults are shown in the following table.
|18.5 – 24.9||Normal|
|25.0 – 29.9||Overweight|
|30.0 and Above||Obese|