BMI Calculator

Check your body mass index against CDC adult BMI categories.

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How We Calculate This

BMI is simply weight (kg) ÷ height (m)² — a quick, population-level screening measure, not a precise individual health assessment. The category thresholds (underweight, healthy weight, overweight, obesity) come from the CDC's adult BMI reference ranges.

Worth knowing: BMI can't distinguish fat mass from lean muscle and bone, so it can misclassify very muscular or very lean people as "overweight" or "obese" even when their body fat is actually low. It also can't account for fat distribution — try our Waist-to-Height Ratio Calculator for another perspective on that. The standard thresholds were also developed largely from data on white/European populations, and both the CDC and a WHO expert consultation have noted that they can misjudge risk for other groups — for example, East and South Asian populations tend to face higher health risk at lower BMI values than the standard cutoffs reflect. Treat it as a starting point for a conversation, not a verdict.

Read CDC's BMI guidance →

Read CDC's note on BMI and race/ethnicity →

Source: WHO Expert Consultation (2004). Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. The Lancet, 363(9403), 157–163.

Read the WHO consultation →