Calculate BMI Index

How to calculate BMI index? Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height and is expressed in units of kg/m², resulting from mass in kilograms and height in meters.

BMI Formula in pounds and iches

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

BMI Formula in kilograms and meters

Formula: weight (kg) / [height (m)]²

With the metric system, the formula for BMI is weight in kilograms divided by height in meters squared. Because 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

How is BMI interpreted for adults?

For adults 20 years old and older, BMI is interpreted using standard weight status categories. These categories are the same for men and women of all body types and ages.

BMI	Weight Status
Below 18.5	Underweight
18.5 – 24.9	Healthy Weight
25.0 – 29.9	Overweight
30.0 and Above	Obesity

Calculate BMI online

cdc.gov

calculator.net

How good is BMI as an indicator of body fatness?

The correlation between BMI and body fatness is fairly strong, but even if two people have the same BMI, their level of body fatness may differ.
Prentice, A.M. & Jebb, S.A., 2001. Beyond body mass index. Obes. Rev., 2(3), pp.141–7.

In general,

At the same BMI, women tend to have more body fat than men.
At the same BMI, Blacks have less body fat than do Whites^13,14, and Asians have more body fat than do Whites¹⁵.
At the same BMI, older people, on average, tend to have more body fat than younger adults.
At the same BMI, athletes have less body fat than do non-athletes.