Although the BMI formula for adults and children is the same, the way the results are interpreted differ. Therefore, what is considered a healthy BMI also differs. For adults, an ideal BMI is between 18.5 and 24.9. A person with a BMI over 24.9 is considered overweight. A person with a BMI under 18.5 is considered underweight.
Along with the height information ,the weight details of the person is also needed to calculate the BMI. BMI is your weight in pounds multiplied by 703 and divided by the square of your height in inches.A BMI less than 18.5 is considered as underweight,BMI of 18.5 to 24.9 is normal,BMI of 25 to 29.9 is overweight and BMI of 30 and above is obese.