Body Mass Index (BMI) Calculator
Calculate your Body Mass Index (BMI) based on your height and weight. Find your ideal weight range and health category instantly.
This tool is for informational purposes only. Consult a doctor or dietitian for health decisions.
BMI Formula and Assessment Range
Body Mass Index (BMI) is an international screening tool used to determine whether a person's weight is in a healthy range for their height. BMI is calculated by dividing weight (kg) by the square of height in metres (m²). According to World Health Organization (WHO) standards: below 18.5 is 'Underweight', 18.5-24.9 is 'Normal', 25-29.9 is 'Overweight', and 30 or above is 'Obese'.
BMI Limitations and Points to Consider
Since BMI only accounts for height and weight, it cannot differentiate body composition (muscle vs. fat ratio). For example, a professional bodybuilder may appear in the 'obese' category due to high muscle mass, yet be in excellent health. For this reason, waist circumference measurement should also be taken alongside BMI.
Example Scenarios
| Height | Weight | BMI | Category |
|---|---|---|---|
| 160 cm | 50 kg | 19.5 | Normal |
| 175 cm | 70 kg | 22.9 | Normal |
| 180 cm | 90 kg | 27.8 | Overweight |
| 175 cm | 110 kg | 35.9 | Obese |
What to Do to Reach Your Ideal Weight?
If your BMI is outside the normal range, it is recommended to approach the ideal range with a balanced nutrition plan and regular physical activity. Keep in mind that BMI is not a diagnosis — it is only a general health indicator; consult an expert for a comprehensive assessment.
Interpreting Your BMI Result Correctly
BMI is a useful screening tool for assessing health risks, but it is not sufficient on its own. An athlete with high muscle mass may have a high BMI without any health risk. Similarly, in older individuals a normal BMI can mask harmful levels of fat accumulation. BMI gives a far more reliable picture when evaluated alongside waist circumference and body fat percentage.
BMI Categories and Health Risk Assessment
According to the World Health Organization, Body Mass Index is assessed in four main categories. Below 18.5 is underweight, 18.5-24.9 is normal, 25-29.9 is overweight, and 30 or above is obese. Since each category carries different health risks, knowing which range an individual falls into is a critical starting point for preventive health planning.
BMI Limitations: Muscle Mass and Fat Distribution
BMI does not distinguish muscle tissue from fat tissue. An athlete who trains regularly with weights may fall into the 'overweight' category due to high muscle mass, yet their health risks are very low. Conversely, in 'thin-obese' individuals who appear slim but have high fat ratios, a normal BMI can mask the real metabolic risk.
Assessment Combined with Waist Circumference
Waist circumference is a more sensitive indicator than BMI for measuring visceral fat, especially in the abdominal area. The World Health Organization defines waist circumference above 80 cm in women and 94 cm in men as high risk. Using these two measurements together allows for a much more accurate assessment of health risks.
BMI and the Need for Different Interpretation in Children
BMI categories are set for adults; the same cut-off points do not apply to children and adolescents due to their growth stages. The World Health Organization uses age- and sex-standardised percentile charts for child BMI assessment. For this reason, interpreting a child's BMI value should always be done in consultation with a paediatric specialist.