BMI Calculator
Body Mass Index in metric or imperial units, with the WHO adult weight category ranges.
Last updated
Educational tool, not medical advice. BMI is a simple screening measure and doesn't account for muscle mass, bone density, age, sex, or ethnicity. See our terms for details.
—BMI
—WHO category
The formula
BMI = weight (kg) ÷ height (m)². The World Health Organization's adult categories are: under 18.5 = underweight, 18.5–24.9 = normal weight, 25–29.9 = overweight, 30 and above = obese. These ranges were developed from population-level data and are a rough screening tool, not a diagnosis — talk to a healthcare provider for an assessment that accounts for your individual body composition.
Nothing entered here is sent to a server — the entire calculation runs as JavaScript in your browser tab.