What BMI tells you
BMI estimates body fatness from height and weight. The standard categories are: under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30+ obesity. It’s a quick screen, not a full health assessment.
Frequently asked questions
How do I enter imperial height?
Convert feet and inches to total inches (e.g. 5′9″ = 69 inches). The formula is BMI = 703 × pounds ÷ inches².
Is BMI accurate for athletes?
Not always — muscle weighs more than fat, so very muscular people can show a high BMI without excess body fat.