Body mass index (BMI) is a tool to estimate the normal weight range of a person based on their height. It is widely used to identify people who are overweight or obese and is a very approximate guide to the percentage of body fat. BMI is defined as body weight divided by the square of your height (in kilograms per square metre).
Use our online calculator to work out your body mass index by entering your height and weight below. You can use metric or imperial (British) units. The calculator will then tell you if you are underweight, normal weight or overweight. Be honest; nobody is watching!
Metric Imperial