Body Mass Index (BMI) Calculator
Enter your height and weight to see your BMI, its category and the healthy weight range for your height.
This tool is for information only and does not replace a doctor or dietitian. Talk to one before making health decisions.
BMI Formula and Assessment Range
Body Mass Index (BMI) is an internationally used screening measure that shows whether your weight is in a healthy range for your height. It is weight (kg) divided by the square of height in metres (m²). Under World Health Organization (WHO) cut-offs, below 18.5 is 'Underweight', 18.5–24.9 'Normal', 25–29.9 'Overweight', and 30 or above 'Obese'.
BMI Limitations and Points to Consider
Because BMI looks only at height and weight, it cannot separate muscle from fat. A professional bodybuilder, for example, can land in the 'obese' category because of high muscle mass and still be in good health. That is why waist circumference should be measured 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 |
How Can You Reach Your Ideal Weight?
If your BMI is outside the normal range, a balanced diet and regular physical activity are the usual recommendation for moving toward it. BMI is not a diagnosis, only a general health indicator. See a professional for a full assessment.
Interpreting Your BMI Result Correctly
BMI is useful for screening health risks, but it is not enough on its own. An athlete with a lot of muscle can have a high BMI without that meaning a health risk. In older adults, a normal BMI can hide harmful fat build-up. Reading BMI together with waist circumference and body fat percentage gives a far more reliable picture.
BMI Categories and Health Risk Assessment
The World Health Organization groups BMI into four categories: below 18.5 is underweight, 18.5–24.9 normal, 25–29.9 overweight, and 30 or above obese. Each category carries different health risks, so knowing which range you fall into is a starting point for preventive health planning.
BMI Limitations: Muscle Mass and Fat Distribution
BMI does not tell muscle tissue from fat tissue. An athlete who lifts regularly can fall into the 'overweight' category because of muscle mass while their health risks stay very low. On the other hand, in 'thin-obese' people who look slim but carry a high fat ratio, a normal BMI can hide the real metabolic risk.
Assessment Combined with Waist Circumference
Waist circumference picks up visceral fat in the abdomen more sensitively than BMI. The World Health Organization defines a waist above 80 cm in women and 94 cm in men as high risk. Using both measurements together gives a much more accurate view of health risk.
Why BMI Is Read Differently in Children
BMI categories are set for adults. Children and teenagers are still growing, so the same cut-offs do not apply to them. The World Health Organization uses percentile charts standardised by age and sex for children. Always interpret a child's BMI with a paediatrician.