BMI Calculator
Body mass index from your height and weight.
How BMI is calculated
Body mass index is weight in kilograms divided by height in metres squared. It's a quick population-level screening figure, not a diagnosis — it doesn't account for muscle mass, bone density, age, or sex, so an athlete and a sedentary person of the same height and weight can have identical BMI but very different body compositions. The standard World Health Organization bands are under 18.5 (underweight), 18.5–24.9 (normal weight), 25–29.9 (overweight), and 30 or above (obese).
What is BMI?
Body mass index (BMI) is a screening measure based on height and weight. It is commonly calculated as weight in kilograms divided by height in metres squared. The result can be compared with standard adult BMI categories, but BMI does not directly measure body fat or overall health.
Use the calculator as a general reference rather than a diagnosis. Children, athletes, pregnant people and some medical conditions may require different approaches to interpreting body size and health.
How the calculation works
For example, a person weighing 70 kg and measuring 1.75 m has a BMI of about 22.9. The formula is 70 ÷ (1.75 × 1.75).
Frequently asked questions
Is BMI a medical diagnosis? No. It is a screening measure and should be considered alongside other health information.
Why does the calculator ask for height and weight? Those are the two values used by the standard BMI formula.