Healthy Weight Range Calculator

Healthy weight range from height

The name is a bit of a joke, but the math is serious: this calculator tells you the healthy weight range for a given height, using the Body Mass Index (BMI) bands the WHO recommends. You work it out with weight = BMI × height², height in meters. The healthy band runs from BMI 18.5 to 24.9. Below 18.5 counts as underweight, 25.0 to 29.9 as overweight, and 30 or more as obesity. So someone who is 1.70 m tall has a healthy window of about 53.5 kg to 72.0 kg, and 63.6 kg sits right in the middle at a BMI of 22.

Applications and context

Clinicians, occupational health programs and most fitness apps lean on BMI for one simple reason: all it needs is your height and weight. That makes it great for looking at whole populations and shaky for any one person. A muscular athlete can read BMI > 25 without an ounce of excess fat, and a couch-bound person with a "normal" BMI can be hiding a lot of visceral fat — the so-called "skinny-fat" profile. To get the real story, look at BMI alongside your waist circumference, your waist-to-height ratio, or a body composition test like DEXA or bioimpedance.

FAQ

Why does BMI use height squared? Back in 1832, Quetelet noticed that adult body mass tracks roughly with height squared, not height cubed. That observation is why the index divides mass by h² rather than h³.

Is BMI accurate for athletes? Often not. Muscle is denser than fat, so a strength athlete can land in the overweight band on BMI while actually carrying very little fat. For those folks, a body composition test is the better call.

Does BMI apply equally to all ethnic groups? No. Metabolic risk tends to show up at lower BMI in Asian populations, which is why the WHO recommends acting at a threshold of 23 rather than 25 for these groups.