BMI uses the same formula for men and women, but body composition differs significantly. Men typically carry less body fat than women at the same BMI and have more muscle mass. Enter your details to see your BMI, WHO category, and the healthy weight range for your height.
After converting any imperial inputs to kilograms and metres, the WHO formula weight(kg) / height(m)^2 produces your BMI in one step. The calculator then maps the result onto the WHO categories and also computes the healthy weight band by rearranging the same formula at the 18.5 and 24.9 boundaries for your height, so muscular athletes can see how close they are to the next category.
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The BMI formula was standardised by the WHO Technical Report Series 894 (2000): BMI = weight(kg) / height(m)². WHO classifies BMI into four categories for adults: Underweight (<18.5), Normal weight (18.5–24.9), Overweight (25.0–29.9), and Obese (≥30.0). BMI does not distinguish between muscle and fat mass and is intended as a population-level screening tool, not an individual diagnostic.
To estimate daily energy needs, try the calorie calculator. For body composition with circumference measurements, use the body fat calculator. To find a reference weight range for your height, see the ideal weight calculator.