Health
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May 14, 2026
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5 min de lecture
BMI Explained: What Your Body Mass Index Actually Means
BMI is a quick screening tool but not a diagnosis. Here is what the WHO categories mean, when BMI fails, and what to do with your number.
Body Mass Index (BMI) compares weight to height. The WHO defines underweight (<18.5), normal (18.5-24.9), overweight (25-29.9) and obese (>=30). It is a population screening tool, not a clinical diagnosis. Athletes with high muscle mass can score "overweight" despite low body fat. Older adults may score "normal" while carrying unhealthy levels of visceral fat. For a fuller picture, combine BMI with body fat percentage, waist-to-hip ratio, and resting heart rate. Use our BMI Calculator to check yours, then explore the Body Fat Calculator for a more complete read.