MyCalculatorHow it works
BMI (metric) is Weight (kg) ÷ Height (m)². In imperial units it's 703 × Weight (lb) ÷ Height (in)².
Example
A person weighing 70 kg at 175 cm has a BMI of about 22.9, in the 'normal weight' range per the standard WHO categories (Underweight <18.5, Normal 18.5–24.9, Overweight 25–29.9, Obese 30+).
Assumptions & limitations
BMI is a simple screening tool and does not directly measure body fat, muscle mass or overall health. It can be misleading for athletes, older adults, pregnant people and some other groups. It is not a diagnosis.
Frequently asked questions
Is BMI accurate for everyone?
No — BMI doesn't account for muscle mass, bone density, age or sex, so it can misclassify very muscular or very lean individuals.
What BMI category ranges are used?
The standard WHO ranges: Underweight below 18.5, Normal 18.5–24.9, Overweight 25–29.9, Obese 30 and above.