BMI (Body Mass Index) is a screening tool that estimates body fat based on your height and weight. It helps identify possible weight problems in adults.

For adults, a healthy BMI is 18.5 to 24.9. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obese. These ranges apply to most adults 20-65 years old.

BMI is a useful screening tool but has limitations. It does not distinguish between muscle and fat, so athletes may have a higher BMI despite low body fat. It also may not be accurate for elderly people or those with certain medical conditions.