BMI Calculator
Body mass index, with the category and healthy weight range.
A screening tool, not a diagnosis. Discuss any concern with a doctor.
How it works
BMI is weight divided by height squared. It was devised in the 1830s to describe populations, not individuals, and it is best read as a rough screening number rather than a verdict.
It does not distinguish muscle from fat, so it misclassifies athletes routinely. It does not account for where fat sits, which matters more for health than how much there is. And its thresholds behave differently across ethnic groups — the overweight threshold is lower for South and East Asian populations.
Common questions
What are the categories?
Under 18.5 underweight, 18.5-24.9 healthy, 25-29.9 overweight, 30 and above obese. These are WHO thresholds for adults.
Is BMI useless for athletes?
For very muscular people, yes. Muscle is denser than fat, so a lean athlete can read as overweight. Waist measurement or a body-fat estimate is more informative there.