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Body Mass Index (BMI) is a quick screening number calculated from your height and weight. Enter your measurements below — metric or imperial — and this free BMI calculator shows your BMI, your category, and your healthy weight range instantly. No sign-up; your numbers never leave your device.
BMI (Body Mass Index) is a quick estimate of body fat based on your height and weight. Metric: weight (kg) ÷ height (m)². Imperial: 703 × weight (lb) ÷ height (in)². It doesn't distinguish muscle from fat — very muscular people can score as "overweight" even with low body fat.
Underweight: below 18.5 · Normal: 18.5–24.9 · Overweight: 25–29.9 · Obese: 30 and above. These are the standard World Health Organization ranges.
The healthy range is the weight that puts your BMI between 18.5 and 24.9 for your height: from 18.5 × height² to 24.9 × height². It's a rough guide, not a personal target — talk to a doctor for advice about your own health.
No. This calculator is for general information only and is not a substitute for professional medical advice. Always talk to your doctor about your health and weight.
Not always. BMI can’t tell muscle from fat, so athletes and very muscular people can land in “overweight” while being perfectly healthy. If you lift regularly, pair BMI with waist circumference or a body-fat estimate. The CDC (cdc.gov/bmi) notes BMI is a screening tool, not a diagnosis.
For adults, 18.5–24.9 is the standard healthy range at any age. For adults over 65, some research suggests 22–27 may be perfectly fine, since a little extra reserve helps with illness recovery. For children and teens, use BMI-for-age percentiles rather than adult cutoffs.
The formula is the same, but body composition shifts after menopause — muscle mass tends to drop and visceral fat rises, which BMI alone won’t show. Women over 50 get the most useful picture by combining BMI with a waist measurement (under 35 inches is the commonly cited target).