BMI Calculator
Enter your height and weight — in metric or imperial units — to get your Body Mass Index and the WHO weight category it falls into.
Your BMI
—
Category
—
Frequently asked questions
What do the BMI categories mean?
The WHO categories for adults are: under 18.5 underweight, 18.5–24.9 healthy weight, 25–29.9 overweight, and 30+ obesity. BMI is a screening measure, not a diagnosis.
Is BMI accurate for athletes?
Not always. BMI does not distinguish muscle from fat, so muscular athletes often score “overweight” despite low body fat. Body composition measures (DEXA, skinfolds) are better for athletes.
How is BMI calculated?
Metric: BMI = weight (kg) ÷ height² (m²). Imperial: BMI = 703 × weight (lb) ÷ height² (in²). Both formulas give the same result.