BMI Calculator
Enter height and weight to get your Body Mass Index, its category, and the weight range that BMI classifies as healthy for your height. Switch between centimetres/kilograms and feet/inches/pounds — the numbers update as you type, and nothing is recorded anywhere.
What BMI can and cannot tell you
BMI is weight in kilograms divided by height in metres squared — a 19th-century ratio that survived because it correlates with population-level health risk and needs only two numbers. The standard cut-offs (18.5 underweight, 25 overweight, 30 obese) come from large cohort studies and apply to average adults.
Its blind spot is that BMI cannot tell muscle from fat: trained athletes routinely land in the "overweight" band while being metabolically healthy, and people with normal BMI can still carry risky abdominal fat. Treat BMI as a screening flag, not a verdict — waist circumference and body-fat percentage fill in what it misses, and any actual health decision belongs with a clinician, not a webpage.
FAQ
- Why does my healthy range look low/high?
- The range shown is simply the weights whose BMI falls between 18.5 and 24.9 for your height. For very tall or short people this range can feel unintuitive; athletes should ignore it.
- Does it work for children?
- No. Children and teens need age-percentile charts; adult cut-offs misclassify them.
- Is my data sent anywhere?
- No. The calculation runs in the page's JavaScript and the values live only in this tab.