BMI Calculator
Quick answer: BMI = weight (kg) ÷ height² (m). Under 18.5 is underweight, 18.5–24.9 normal, 25–29.9 overweight, and 30+ obese. Enter your numbers below in US or metric units for an instant result and your healthy weight range.
What your BMI does and doesn't tell you
BMI is a population screening tool: cheap, fast and surprisingly predictive of health risk at the group level. At the individual level it has blind spots — muscle mass, fat distribution and ethnicity all shift what a given number means. Treat it as a starting flag, not a verdict; waist circumference and body-fat percentage fill in what BMI misses.
Why BMI matters in the GLP-1 era
BMI thresholds became newly practical with modern weight-loss medications: 30+, or 27+ with a comorbidity, is the standard label criterion for semaglutide and tirzepatide. If that's your situation, our GLP-1 weight-loss calculator projects what trial-average results would look like from your starting weight.
FAQ
Is BMI accurate for muscular people?+
No — BMI can't distinguish muscle from fat, so muscular people often read 'overweight' at low body-fat levels. For a better picture, pair BMI with a waist measurement or the body fat calculator on this site.
What BMI do you need for GLP-1 medications?+
US labels for Wegovy and Zepbound set thresholds at BMI 30+, or 27+ with a weight-related condition such as high blood pressure or type 2 diabetes. Prescribers make individual decisions beyond the number.
Is BMI different for men and women?+
The standard BMI categories are identical for adult men and women, though women naturally carry more body fat at the same BMI. Age also shifts interpretation — slightly higher BMIs in older adults are not necessarily worse.
Educational tool — estimates only, not medical advice. Consult a licensed healthcare provider for individual guidance.