Body Mass Index (BMI) Calculator
Check weight-to-height ratio according to WHO standards.
How Body Mass Index is calculated
BMI is calculated using the Quetelet formula: weight in kilograms divided by height in meters squared. It's a quick, approximate measure of the relationship between weight and height, recommended by the World Health Organization (WHO).
BMI = Weight (kg) ÷ Height² (m)
WHO classification: below 18.5 — underweight, 18.5–24.9 — normal, 25.0–29.9 — overweight, 30.0+ — obesity. The figure is approximate and doesn't account for muscle mass, age, or body frame, so it can be inaccurate for athletes and older adults.
This calculation is for informational purposes only and is not medical advice or a diagnosis. For questions about weight and health, consult a doctor.
FAQ about Body Mass Index
Is BMI accurate for everyone?
No. BMI doesn't distinguish between muscle and fat mass, so athletes with high muscle mass may get an inflated result. It's also less accurate for children, pregnant women, and older adults.
What BMI is considered normal?
Under the WHO classification, the normal range is 18.5 to 24.9. But this is a general guideline, not a medical diagnosis.
Does this calculator replace seeing a doctor?
No. BMI is only an approximate indicator for general information. For questions about weight, body composition, or health, always consult a doctor or a dietitian.
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