BMI Formula

How is BMI calculated and interpreted?

Calculation of BMI
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 inchesFormula: 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