Body Mass Index (BMI)

Medical Dictionary

BMI or Body Mass Index refers to the amount of body fat a person has. It is calculated by dividing your weight (in kilograms) by your height in meters squared to calculate a value, which should optimally be within the range of 18.5-24.9. BMI's below 18.5 are generally considered underweight, those 25 and above are classed as overweight, and above 30 is obese.

An elevated BMI is associated with an increased risk of health problems such as heart disease, diabetes and high blood pressure. Note there are some exceptions to the BMI calculation such as well trained athletes who have an elevated BMI due to muscle mass but are are not at risk of the above diseases.

This tool needs Javascript enabled to run.The formula for calculating your body mass index is:
BMI = weight (kilograms) / (height (metres) * height (metres))

For example:
A man who weighs 85 kilograms and is 1.8 metres tall would have a BMI of
BMI = 85 / (1.8 * 1.8)
BMI = 85 / 3.24
BMI = 26.2