BMI Calculator

Enter your height and weight to see your body mass index and the healthy weight range for your height.

Results

Body mass index (BMI)
24.2
Category
Healthy weight
Healthy weight from (kg)
53.5
Healthy weight up to (kg)
72

BMI is a screening measure for adults over 18. It can mislead for muscular athletes, during pregnancy, and for children and older adults. It is not a diagnosis; ask your doctor for an assessment.

Body mass index (BMI) is a simple ratio that shows whether your weight is low, healthy or high for your height. Your weight in kilograms is divided by the square of your height in metres.

For adults the World Health Organization classes a BMI under 18.5 as underweight, 18.5–24.9 as healthy, 25–29.9 as overweight and 30 or more as obesity. The calculator also shows the lowest and highest weight that fall in the healthy range for your height.

How to calculate BMI

  1. Choose metric (cm, kg) or imperial (in, lb) units.
  2. Enter your height and weight.
  3. Read your BMI, its category and the healthy weight range for your height.

BMI formula

  • BMI = weight (kg) ÷ height (m)²
  • Imperial: BMI = 703 × weight (lb) ÷ height (in)²
  • Healthy weight range = 18.5 × height² to 24.9 × height²

BMI example

Someone 1.70 m tall weighing 70 kg has a BMI of 70 ÷ (1.70 × 1.70) = 24.2, which is in the healthy range. For that height the healthy range is roughly 53.5 to 72 kg.

BMI: common questions

What is a healthy BMI?

For adults, 18.5 to 24.9 is considered healthy. 25 and above is overweight and 30 and above is classed as obesity.

Is BMI accurate for everyone?

No. Muscular athletes can score high without excess fat, and older adults can score low while carrying little muscle. It is not used the same way in pregnancy or for children. BMI is a screening measure, not a diagnosis.

How is BMI assessed for children?

The formula is the same, but the result is read against age- and sex-specific growth charts (percentiles). Ask your paediatrician.

Is BMI the same as body fat percentage?

No. BMI only uses height and weight and cannot tell fat from muscle. Our body fat calculator estimates fat percentage from tape measurements.