How BMI is calculated
BMI is weight in kilograms divided by height in metres squared (kg/m²). Standard adult categories: under 18.5 is underweight, 18.5–24.9 is a healthy weight, 25–29.9 is overweight, and 30 or above is obese. BMI is a screening measure, not a diagnosis — it doesn't distinguish muscle from fat, so athletes and older adults should interpret it with care. Talk to a healthcare professional about what your number means for you.