Body Mass Index (BMI)

Body Mass Index (BMI)

Body Mass Index (BMI) is a useful indicator of whether an individual has a 'healthy' body weight in relation to his/her height, or falls into the category of 'overweight', obese, or underweight, all associated with well known health risks.

BMI is calculated as:

weight (in kilogrammes)

height (in metres) 2


For adults, the accepted healthy range is 19-25 (below 18 is underweight, 25-30 overweight, 30-40 moderate obesity, over 40 severe obesity).

A man weighs 95 kg and his height is 1.8 metres.

Calculate his BMI - Answer:     


He decides to go on a diet, and after 3 months his weight is 89kg 

Calculate his new BMI - Answer:     


What weight must he reach in order to achieve a healthy BMI? 

Answer:     

Note: It is worth pointing out that height is assumed not to change in these scenarios.