What this calculator measures
BMI (Body Mass Index) is a screening tool that compares body weight to height. It categorizes adults into ranges (underweight, healthy, overweight, obese) that correlate with certain population-level health risks. It does not measure body fat directly or distinguish muscle from fat — a limitation that makes it an incomplete picture for trained individuals.
How this calculator works
BMI equals weight in kilograms divided by height in metres squared. Adult categories from the CDC and WHO apply from age 20: underweight < 18.5, healthy 18.5–24.9, overweight 25–29.9, obese ≥ 30. This calculator also displays the weight range that would put you in the healthy-BMI band at your height.
How to use your result
Treat BMI as a quick screen, not a verdict. If your BMI registers as 'overweight' but you are muscular and lean, pair this with a body fat percentage estimate from the body fat calculator for a clearer picture. Conversely, if BMI reads 'healthy' but your waist circumference is high, check your waist-to-height ratio.
Important limitation
Calculator results are estimates. Pregnancy, eating disorders, medical conditions, injuries, or concerning symptoms require qualified professional guidance.