The body mass index (BMI) is a measure that uses your height and weight to work out if your weight is healthy.

BMI ranges

For most adults, an ideal BMI is in the 18.5 to 24.9 range.

For children and young people aged 2 to 18, the BMI calculation takes into account age and gender as well as height and weight.

If your BMI is:

• below 18.5 – you’re in the underweight range
• between 18.5 and 24.9 – you’re in the healthy weight range
• between 25 and 29.9 – you’re in the overweight range
• between 30 and 39.9 – you’re in the obese range