Published Tue, 2010-12-21 00:29; updated 4 years ago.

BMI is a good way to check if you’re a healthy weight. Use this BMI calculator to check the whole family and find helpful information and advice. BMI is a measure of whether you’re a healthy weight for your height.


For adults, the body mass index (BMI) is used to calculate whether a person is underweight, a healthy weight, overweight or obese for their height. It allows for natural variations in body shape giving a healthy weight range for a particular height. It divides the adults weight in kilograms by their height in metres squared.


However it is interpreted differently for children. The age and sex of children are important and their BMI is compared with the measurements of other children. These are then split into percentiles to try assign whether their BMI is within the healthy range according to height, weight, age and sex. For example, if children are found to be overweight, this means that their BMI is higher than average for a child of their age and sex.

Go to the NHS Choices BMI health weight calculator.