BMI Calculator
Calculate your Body Mass Index using WHO (World Health Organization) standards
About BMI
WHO Standards
This calculator uses the World Health Organization (WHO) BMI classification system, which is the international standard for assessing weight status.
BMI Categories
- Underweight: BMI < 18.5
- Normal: BMI 18.5 - 24.9
- Overweight: BMI 25 - 29.9
- Obesity Class I: BMI 30 - 34.9
- Obesity Class II: BMI 35 - 39.9
- Obesity Class III: BMI ≥ 40
Limitations
BMI does not account for muscle mass, bone density, overall body composition, or racial and sex differences. It may not be accurate for athletes, elderly, or pregnant women.
Frequently asked questions
What is BMI?
Body Mass Index (BMI) is weight in kilograms divided by height in metres squared. It is a screening tool for weight categories, not a direct measure of body fat.
What BMI is considered normal?
WHO classifies 18.5–24.9 as normal weight for adults. Under 18.5 is underweight; 25–29.9 is overweight; 30 and above is obesity.
Is BMI accurate for athletes?
Muscular adults may have a high BMI despite low body fat. Use BMI alongside waist circumference, fitness, and clinical assessment.