The standard weight for a 1.65 meter girl should be about 50-65 kg. 1. Normal weight is generally measured by the body mass index BMI, calculated as BMI = weight (kg) ÷ height squared (m²), the standard value of adult BMI is between 18.6-23.9Kg/m². So the standard weight for a 1.65 meter girl is about 50~65kg. 2. There is another algorithm is standard weight = height (cm) – 55, so the standard weight of 1.65 meters girls is 60 kg, up and down 10% are normal. 3. If the weight is too low, it may cause malnutrition and other hazards, and you should ensure sufficient energy intake on a daily basis. Excessive weight can increase the risk of hypertension, diabetes, cardiovascular disease, should actively control diet, moderate exercise to reduce weight. For the sake of health, weight should be controlled to the ideal level.