BMI Formula

The body mass index (BMI) is a statistic developed by Adolphe Quetelet in the first half of the 19th century for evaluating body fat. It is not related to gender and age. It uses the same formula for men as for women and children.

For a given height, BMI is proportional to mass. However, for a given mass, BMI is inversely proportional to the square of the height. So, if all body dimensions double, and mass scales naturally with the cube of the height, then the Body Mass Index doubles instead of remaining the same.

Calculating your BMI is an easy way to tell if your weight is putting your health at risk.

Here is the BMI formula to help you to calculate your own body mass index:


English BMI Formula

Using the English system, your BMI is your Weight in pounds (lbs) divided by your height in inches (in) squared and multiplied by a conversion factor of 703.

BMI = ( Weight (lb) / Height (in) 2 ) x 703

Metric BMI Formula

Using the metric system, your BMI is your Weight in kilograms divided by your height in meters squared.

BMI = Weight (kg) / Height (m) 2

Learn more about calculating your BMI and understanding its implications for your health by visiting our comprehensive guide on Body Mass Index (BMI) here.

BMI Examples

English system:

An example of calculating body mass index using the English system for the formula:

  • My Weight = 150 lbs.
  • My Height = 5'5" (65 inches)
  • BMI Calculation: [150 ÷ (65)2] x 703 = 24.96

Metric system:

An example of calculating BMI using the metric system for the formula:

  • My Height = 165 cm (1.65 m).
  • My Weight = 68 kg
  • BMI Calculation: 68 ÷ (1.65)2 = 24.98

To calculate your BMI, you can use our Best BMI calculator:

In general, by Knowing your Body Mass Index measurement using the BMI formula, you can determine if you're at risk for BMI Related Disease.