Enter your weight in kilograms and height in centimetres to calculate your BMI and see your WHO weight category instantly. All calculations run locally in your browser.
Centimetres are divided by 100 to get height in metres, then the WHO formula weight(kg) / height(m)^2 produces your BMI directly in metric units with no unit conversion needed. The resulting number is matched against the WHO thresholds (under 18.5, 18.5 to 24.9, 25 to 29.9, and 30 or above) so the category label updates instantly as you adjust either input.
All calculations happen locally in your browser tab. Our servers are not involved at any point.
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.