Body mass index compares your weight to your height to give a quick, standardized picture of whether you sit in a healthy range.
Enter your weight in kilograms and height in centimeters below — you will get your BMI, the World Health Organization weight category it falls into, and the weight range that corresponds to a healthy BMI for someone your height.
For educational purposes only — not medical advice.
How to use
- Enter your weight in kilograms.
- Enter your height in centimeters.
- Press Compute to see your BMI.
- Read your WHO category and the healthy weight range for your height.
- Re-check whenever your weight changes meaningfully — trends matter more than a single reading.
Frequently asked questions
What is BMI?
BMI (body mass index) is a screening measure calculated by dividing your weight in kilograms by the square of your height in meters. It estimates whether your weight is in a healthy proportion to your height.
What is a healthy BMI?
For most adults, the World Health Organization classifies 18.5–24.9 as normal weight, below 18.5 as underweight, 25–29.9 as overweight, and 30 or above as obese.
Is BMI accurate for everyone?
No. BMI does not distinguish muscle from fat, so very muscular people can score high while being healthy, and it says nothing about where fat is stored. It is a screening tool, not a diagnosis.
Does BMI work for children?
Children and teenagers are assessed with age- and sex-specific BMI percentiles rather than fixed adult cutoffs, so treat the result here as a rough guide for anyone still growing.
How often should I check my BMI?
For most people, once a month or at a routine check-up is plenty. Day-to-day weight changes are mostly water, so trends over weeks are far more informative.
Can BMI be wrong for older adults?
It can lean optimistic: older adults tend to lose muscle, so a normal BMI can hide a higher body-fat percentage. Waist measurement and professional advice are useful complements.