The standard weight for a 173cm tall boy should be between 55.37kg and 71.53kg. Calculation of standard weight can be based on the standard of body mass index (BMI), which is an internationally used standard to measure the degree of fatness and thinness of the human body and whether it is healthy or not. The formula for calculating BMI is BMI = weight (kg) ÷ height (㎡), where weight is in kg and height is in m. The BMI calculated based on height and weight is between 18.5kg/m2 and 23.9kg/m2, which is the normal weight, i.e. standard weight. By inverse calculation, the standard weight for a male with a height of 173cm should be between 55.37kg and 71.53kg. This standard applies to adults, and is the same for men and women, but does not apply to women during pregnancy. Boys with a height of 173cm, if their weight is higher than 71.53kg, they should strengthen exercise and reasonably control their diet to reduce their weight to normal; if their weight is lower than 55.37kg, they can increase their nutrition appropriately. Being too thin or too fat is not conducive to health.