bmi number for adults
Muscle weighs more than fat, so a muscular person may appear to have a higher BMI, or a frail, inactive person may have more body fat than is healthy. For adults 20 years and older: 1  A BMI below 18.5 (shown in white) is considered underweight. 2  A BMI of 18.5 to 24.9 (green) is considered healthy. 3  A BMI of 25 to 29.9 (yellow) is considered overweight. 4  A BMI of 30 or higher (red) is considered obese.