Normally, a daily milk intake of around 800 ml is appropriate for a three and a half month old baby, but it needs to be decided according to each baby’s own needs. For three-and-a-half-month-old babies, you need to follow the principle of feeding on demand. Usually, the daily milk intake is around 800 ml, and you can feed them 5-6 times a day, with each feeding amounting to around 150 ml. However, different children have different needs for milk, and the exact amount of milk to be fed needs to be decided according to the baby’s own situation and needs. In addition, the amount of milk a baby drinks daily will not be fixed. Occasional more or less is usually of little consequence, and as long as the baby’s growth and development are normal, there is no need to worry too much. If your baby is lagging behind in growth and development, you should consult a doctor promptly. Babies who are not feeling well should seek prompt medical attention to avoid delay.