BMI calculator
Enter your weight and height to get your body mass index and the standard adult category, plus the weight range that corresponds to a BMI of 18.5 to 24.9 at your height.
How the bmi calculator works
BMI divides your weight in kilograms by your height in metres, squared. For adults, the World Health Organization groups the result into bands: under 18.5 is underweight, 18.5 to 24.9 is the healthy range, 25 to 29.9 is overweight and 30 or above is in the obesity range.
The formula behind it
BMI = weight (kg) ÷ height (m)²
Imperial: BMI = 703 × weight (lb) ÷ height (in)²
A worked example
A person weighing 70 kg who is 175 cm tall: height is 1.75 m, so 1.75² = 3.0625. BMI = 70 ÷ 3.0625 = 22.9, which is in the healthy range. The healthy weight range at that height is about 56.7 to 76.3 kg.
Questions people ask
Is BMI accurate for athletes?
Not always. Muscle weighs more than fat, so a very muscular person can have a high BMI without carrying extra fat.
Does it work for children?
No. Children are assessed on growth charts that compare them with others of the same age and sex.
What is a healthy BMI?
For most adults, 18.5 to 24.9, but your doctor can tell you what is right for you.
Is this medical advice?
No. It is general information. Please speak to a healthcare professional about your health.