The Body Mass Index (BMI) is a measure that uses your height and weight to work out if your weight is healthy.
For most adults, an ideal BMI is in the 18.5 to 24.9 range.
BMI takes into account natural variations in body shape, giving a healthy weight range for a particular height.
As well as measuring your BMI, healthcare professionals may take other factors into account when assessing if you’re a healthy weight.
Muscle is much denser than fat, so very muscular people, such as rugby players, weight trainers and athletes, may be a healthy weight even though their BMI is classed as obese.