A body mass index of 18.5 to 23.9 Kg/m² for girls is the normal range. Body mass index, also called body mass index, is a standard used to determine obesity or not, and more accurate, the English abbreviation is BMI. The international standard is 18.5～24.9Kg/m² as normal, while our BMI is 18.5～23.9Kg/m² as normal. The body mass index is calculated based on the height and weight of the girl, BMI = weight (kg)/height squared (m²). A BMI of 24 to 27.9Kg/m² is overweight, a BMI of 28kg/m² is obese, and a BMI of less than 18.5Kg/m² is emaciated. If you are obese or emaciated, you can do physical exercise, combined with a reasonable diet, to keep your weight within the normal range, or you can seek guidance from a nutritionist.