Use your height and weight to estimate your body fat. Your BMI can also be used to gauge your risk for health problems like heart disease, high blood pressure, Type 2 diabetes, gallstones, breathing problems and some cancers.
Note that BMI can be used for most people, but it may:
overestimate body fat in athletes or people with a muscular build
underestimate body fat in older people, or those who have lost muscle.
Go to the Heart Foundation's BMI calculator.