How BMI is calculated
BMI is weight divided by height squared (kg/m² in metric, or weight in pounds × 703 ÷ height in inches squared for imperial). It’s a simple screening ratio, not a direct measure of body fat — the calculator handles the unit conversion automatically so you can enter either metric or imperial values.
What the WHO categories mean
The World Health Organization defines standard adult ranges: under 18.5 is underweight, 18.5–24.9 is a healthy weight range, 25–29.9 is overweight, and 30+ falls into obesity classes. These thresholds are population-level screening guidance, not a diagnosis for any individual — the calculator shows which range your BMI falls into using these published cutoffs.
Where BMI falls short
BMI doesn’t distinguish muscle from fat, so athletes and very muscular people are often classified as “overweight” despite low body fat. It also doesn’t account for fat distribution, age, or sex-based body composition differences. It’s best used as one data point alongside other measures (waist circumference, body fat percentage) rather than a standalone health verdict.
Why use UtilityApps for this
Your height and weight are calculated locally in your browser and never stored or sent anywhere. No signup, and it works offline once the page has loaded.