Body Mass Index (BMI) is a tool for indicating weight status. The BMI table on the right is for adults over 20 years old. BMI is defined as weight in kilograms divided by the square of height in metres. For example, a person who weighs 72 kg and whose height is 1.77 m will have a BMI of 23, ie:

BMI = 72 / 1.77² = 23

As BMI increases the risk of some diseases and death increases. For further information see the World Health Organisation and the Health Profile of England. The relationship between height and weight for each BMI category is further illustrated by the chart and metric or imperial tables below.