Updated 10 February 2014

Body Mass Index (BMI)

A quick definition of BMI.

What is BMI?

Body mass index (BMI) is a simple index of weight-for-height that is commonly used in classifying overweight and obesity.

How to calculate BMI

BMI is calculated by dividing weight in kilograms by height in metres squared.

For example, if you are 1.65m tall and weigh 85kg: weight / height squared = 85 / 1.65 x 1.65 = 85 / 2.72 = 31.25. Then your BMI would be 31.25.

Use Health24's BMI Calculator

What your BMI means

  • BMI between 18 and 25: Normal weight
  • BMI between 25 and 30: Overweight
  • BMI greater than 30: Obese

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